Mower Deck Belt Replacement – Step by step
Replacing belts on your mower is like replacing tires on your car; there are only so many miles in them. Replacing a deck belt can be a challenge, especially if the mower throws the belt and you don’t know the routing, but we’ll get it figured out!
Getting the correct belt is the first important step. Some manufacturers place a label detailing the belt part number and belt routing. Try under the hood or under the footrest; if not, check out “Belt routing.”
Deck types vary. Some are easy to work on, some not so much. It’s important to check over the deck looking for any damaged or loose components, especially if your old belt was damaged and not just worn out. You don’t want to damage the new belt needlessly.
Most mowers won’t require deck removal to fit the belt; others will. So take some time and consider the routing, don’t put extra work on yourself. Take lots of photos; it saves time and head-scratching later.
What’s Involved?
Fitting the new belt means removing some plastic protective covers. And in most cases, it involves wrapping the belt around the pulleys and making sure the belt guide (guide not on all pulleys) is on the outside of the belt. The last pulley to fit is the crank pulley (engine pulley).
Tensioned or Not
A tension-ed belt is a deck drive belt that is always tight on the pulleys. Push-button blade engages type mowers usually run an always tension-ed belt. Replacing it will require manhandling the belt onto the side of the crank pulley, then turning the crank pulley clockwise by hand until the belt slips on.
If your mower has a lever, then you likely have a slack belt which is then tensioned by moving the blade to engage the lever. This type of belt is easier to replace and will take no time at all.
Tensioned – This type of belt is always tight on the pulleys.
Un-Tensioned – This type of belt setup is slack on the pulleys until you engage the blades.
What Deck Type?
Cutting deck setup types vary from side discharge; rear discharge; mulching decks; front decks; cutting, and sweeping.
They may have features such as single-blade; twin-blade; tri-blade; tensioned belt; manual tensioned belt; electromagnetic blade engagement; fan assisted deck; timed overlapping blades, and so on.
The one thing they all have in common – is the deck drive belt. It’s how engine power is transferred into cutting power.
Timed Deck
A timed deck means both your mower blades are set at a fixed angle in relation to each other. The toothed belt maintains the blade position; this allows the blades to overlap.
Some say the overlapping blades give a superior cut; I like the lawn finished with the overlapping twin cut, especially the smaller decks.
This deck type is also referred to as an interference deck. They call it Interference because if the blades go out of time, they’ll smack each other.
Resetting the timing of the blades or replacing the belt is a job that can be done without much difficulty, but it does require removing the deck, tension assembly, and various plastic guards. No special tools are needed.
Rear – Rear discharge is great at collecting grass but doesn’t like long grass so much.
Timed – Timed deck has a toothed belt that can break or slip out of time. Timing the blades allows them to overlap.
Mulching – Some decks will have a flap that closes off the chute when the operator wants to mulch.
Side Discharge – Side discharge is great for tall grass and rough terrain.
Measuring The Belt
A belt will be marked with a type code, length, and part number. Belts are usually measured by their inside length (Li) or outside length (La); if you can find this info on the side of your old belt, great! But usually, it’s worn away.
Some mowers like Husqvarna place a sticker inside the hood with a list of helpful part numbers like belts, filters, plugs, etc.
What Belt Width? – The width and depth of a belt are also very important. A new V belt should fit snugly into a v pulley; the belt should sit just proud of the pulley’s shoulder. A belt that sits further down into the pulley is worn out.
What Belt Length? – If your belt was shredded, then you’ll need your make and model number to order the correct belt. An easy way to measure an old belt – use a string to follow the outside of the belt; now measure the string.
This measurement will be marked on belts by the letters La (outside measurement); alternatively, run the string around the inside of the belt; this measurement is the Li measurement.
A faster way to measure an intact belt is to make a circle of the belt and measure inside to inside, then multiply by 3.14. The result is the Li belt size.
Sizing – Sometimes easier said than done!
Markings – Check under the hood of your mower; you may get lucky with a part number sticker, but be cautious with the Husqvarna labeling; they are often wrong belt part numbers.
Check your old belt for markings; if none, get the tape and some string. These belts are measured in mm.
Pulley – The new belt will be the full width of the pulley. Worn belts usually stretch in length and become narrow in width.
Check Belt Routing
Belt routing, needless to say, is important. On some mowers, it’s possible to put a belt on the backways, which makes the blades turn backward. Not much use for yard work.
If you can, make a diagram or take some pictures of the old belt in place. First, you’ll need to remove both plastic protection pulley covers, one on each side. Some mowers have a handy sticker showing the deck belt routing under the footrest.
That’s great advice, but what if your belt has snapped or derailed? Then you’ll need to check out the links below. Bear in mind, even if you don’t see your maker in the list, check the link out anyway because lots of make share the same decks.
Look at the pulley configuration to see if yours looks similar.
Belt Routing Links
The following link to Google belt routing pictures:
Sticker – Check under the footrest of your mower; some models have a belt routing sticker. This sticker is on a Husqvarna tractor.
Check out the Amazon link below for deck belts.
What Belt Type?
Belts are belts, right? Well, No. The correct belt is crucial. An ill-fitting or wrong-type belt will cause endless trouble. Throwing the belt, vibration, poor cutting, and collecting, and because the belt doesn’t fit correctly, it won’t last very long. I had one customer who fitted a belt that was so tight it broke the end of the crankshaft. Ouch!!
There are many different types of belts; however, when it comes to lawnmowers, they are usually fitted with a standard V-type belt. Other belts used are AA belts, timed belts, and poly V belts.
Sure, you can fit a basic quality belt with a polyester cord, but it’s going to wear out quickly; for durability, you’ll want Kevlar; they cost more but last a lot longer. Some models will only work well with OEM belts, like John Deere and MTD.
I recommend fitting only OEM (Original Equipment Manufacturer). Fitting a belt can be a challenge. Reassembling and discovering what doesn’t work right can be demoralizing.
How to change the belt, pulleys and spindle on your 42″ John Deere 100 series riding tractor
V Belts
V belts are so-called because of their cross-section shape (wider at the top than the bottom). They are used almost exclusively to drive power from lawn tractor engines to their transmissions. They are also used to drive deck blades. The V belt drives power from one side of the belt only.
They come in different heights/widths and are marked type A, B, C, D. The most common V belts used on mowers are the A and B types, and obviously, they come in a long list of lengths.
Each belt is marked by type and belt length; it may also have a part number. Unfortunately, the markings usually wear off, making the ID process difficult.
AA Hex Belts
The AA belt is a double-sided hexagonal belt; it is mostly used on tractor mower decks to drive the blades. The belts are unique as they have the ability to drive from either side of the belt.
AA Hex Type – This is a double-faced belt; it gives greater flexibility to deck design, as it allows both sides of the belt to drive. It’s used on higher-end tractor decks.
Toothed (Timed) Belts
A mower-toothed or timed belt does two jobs, it transfers power and, at the same time, keeps the mower blades from hitting each other. The toothed belt is a very exact belt in that the teeth of the belt must match that of the mower cogs.
Timed Belt – This type of belt has become more popular in recent years. It’s fitted to mower decks with overlapping blades.
A Type
A Type.This is the most common type of lawn tractor belt; it’s used by many lawn tractor drive systems and most decks too.
B Type
The B-type belt is a heavy-duty A belt; it’s an older well-fed brother.
Check Belt Wear
Belts have a difficult job and can be the cause of various issues. Regular inspection will tell you if your belt is at the end of its life. Things to look for are flat-spotting, glazing, cracking, fraying, and contamination.
As you know, a V belt should sit just proud of the pulley shoulder; if it’s a lot lower than the shoulder of the pulley, it’s worn out.
How Long Do They Last?
The life of a belt is hard to gauge, it really depends on how much grass you’re cutting and how heavy the workload is, but usually, we’re talking years. Typically a belt should be changed after 3-4 years, but we know this doesn’t happen.
A worn or damaged pulley can shorten the life of your belt. An engine or transmission oil leak can destroy the belt, you can try cleaning it, but it causes slip. A derailing belt can get twisted and damaged, and a mower that throws belts regularly probably has a worn or damaged pulley.
But the real killer of belts – tall, heavy grass jams the blades, which causes flat spots on the belt. The flat spot will then cause a lot of vibration, which in turn can throw the belt.
Belt damage is usually caused on the first cut of the season when the grass is heavy. So if your grass is tall and heavy, just take a little off on the first pass and make a second pass with the deck a notch lower. Yes, it’s twice the mowing, but it’s better for your mower and your lawn.
Flat Spot – Flat spotting is usually caused when the blade jams, but the engine pulley keeps running. This has a grinding effect on the belt.
The flat spot will cause excessive vibration in the mowing deck. The fix is – Replace the belt.
Blistering – This can happen when a belt gets old, and the material starts to break down. Your mower won’t cut or collect very well. Better to take care of it now, before it breaks.
Glazing – This belt has a shiny hard surface that is not much good for traction. A belt like this will cause horrible vibration in the mowing deck.
Frayed – Wear and tear, this belt is at the end of its useful life.
Cracked – Natural wear and tear
Check Pulley Wear
A pulley’s job is to route the belt around the chassis of the mower or mowing deck and transfer power from the engine pulley to the driven pulleys. As a rough guide, pulleys usually wear out at the same time as a belt, so best to check them while you have the belt removed.
Tension and idler pulleys should move freely, be quiet when spun, and should feel smooth when turned. If they’re worn, now’s the time to take care of it; when a pulley bearing breaks, it will likely damage the belt.
Spin To Test
You don’t need to remove them to check. Spin them while the belt is off; they should be smooth and quiet. Changing them now is easy.
Bearings
Most pulleys come with the new bearings pressed in place; the exceptions are driven pulleys (Mandrel, engine, or transmission pulleys).
Pulley Types
Pulleys come in all sizes, some metal and some plastic. Tensioners and idlers will have a bearing fitted, and when it wears out, the whole pulley is replaced. Pulleys are usually broken into two main types, flat or V.
A flat pulley is not a driven pulley; it runs on the back of the belt, which isn’t powered (unless it’s on a AA belt).
A V pulley can be driving, driven, tensioner, or idler. A V pulley is described as a driven pulley if it’s connected directly to the output, such as a transmission or a blade Mandrel.
The driving pulley is the engine pulley; it’s the pulley supplying the power. Both the driven and driving pulleys are fixed to shafts using a key and key-way.
A tensioner pulley is part of a moving arm, which, when operated, applies tension to a belt. A tensioner pulley can be a flat or V pulley.
A stationary pulley is usually known as an idler, and its job is to route the belt around the chassis of the mower or mower deck; they can be flat or V-type.
Pulleys – Metal or plastic, V type or flat, driven or idle. So many choices.
V Pulley – This is a V pulley; the driving side of the belt is making contact with the pulley.
Flat Pulley – A flat pulley on a V belt setup is never a driven pulley. Its job is to change the direction of the belt and guide it to the next pulley.
Fitting A Belt
Fitting a cutting blade deck belt that is just worn is the easiest, as you can see the routing of the old belt, and make a diagram or take pictures. Removing the old one also gives you an idea of how challenging fitting the new one will be.
As you know, there are a few variations of deck belt setups; most mowers will have one belt to drive the blades that are either a tension-ed or a un tension-ed belt. The belt can be fitted to both of these types of setups without removing the deck from the mower.
The timed belt setup is a little more involved but not complicated. It has two belts as do so some of the larger John Deere mowers. They can be a challenge as they have many pulleys, and you’ll need to remove the deck.
Pulley Covers
Likely you’ll have already removed the two plastic pulley protection covers, one on each side of the deck. Usually, 2 or 3 screws on each side. They’re not there to protect the pulley. They’re there to protect us from catching body parts in the pulleys.
The latest generation mowers are far more challenging to access as the nice people in the health and safety dept. have been working nights and weekends to find new ways to challenge us.
Removing Belt
Here’s a quick run-through of what we’ll be doing, but it’s all covered in the steps below with pictures. With the covers removed, start by removing the belt from the engine pulley. Often the engine pulley will have a belt guide; its job is to prevent the belt from derailing. Depending on the type of belt guide (if fitted), you may need to remove them first.
As you know, some belts will be tensioned all the time. By tension-ed, I mean the belt is tight around the engine pulley all the time.
The belt tensioner will allow for movement (it’s spring-loaded) so the easiest way to do this is by pulling the belt over the side of the engine pulley and then, with both hands, turning the engine pulley until the belt falls off (Removing the spark plug makes turning the pulley easy).
With the belt off the engine pulley, it’s easy to guide it off the other pulleys. Check your old belt against your new belt, just to be sure.
The un-tensioned belt is simple to fit, and by un-tensioned, I mean the belt is loose around the engine pulley until you engage the blades. The belt can usually be maneuvered around the guides without much trouble.
As with the tension-ed belt, remove the belt from the engine pulley first.
Fitting Belt
Reference your diagram or pictures of routing. Refitting the belt is identical except in reverse order, fitting the engine pulley last by pulling the belt onto the side of the pulley and turning the engine over.
Timed Belt
Most mowers have a simple deck belt setup, like the one covered in this guide is more complex. The demo mower used here has two deck belts driving the mowing deck.
The first one is the main input belt which is powered directly by the engine. This belt is easy to replace, and you don’t need to remove the deck, just some plastic covers.
The second belt is the output belt, and it turns both blades in time. This allows the cutting blades to overlap and catch that annoying tuft of grass you sometimes see in the middle of your cutting strip.
To replace the output belt also known as a toothed belt or timed belt, we need to remove the deck from the mower. It’s not difficult to do, and the whole job shouldn’t take more than an hour.
This guide covers a timed deck belt replacement procedure. Most timed decks will look something similar. It’s more complex than other deck belt setups but not difficult to work on. In this guide, I will: remove the deck; inspect belts; replace the belt; tension the belt; set the timing of the blades.
Tools
No special tools are needed on this mission, but an impact gun would make life a lot easier. When you try to open bolts attached to pulleys, they tend to spin, which is a real pain. Sure, you can wedge it or grab it with grips, but you risk damaging the face of the pulley, and that in turn can damage your new belt. Nooo!
The impact makes small work of pulley bolts, and the better brands have a torque setting built-in which makes reassembly a gift. It’s a super tool to have in the trunk of your car; it makes changing a wheel look NASCAR slick. So treat yourself or drop a few hints before fathers day.
Chute – On this model mower, the chute is fitted through the center of the mower. Not all mowers will have a chute like this. If your mower is side discharge, then you don’t have one.
Remove – As said earlier, you may not need to remove your deck to fit a belt. On this model mower, removing to fit the belt just makes life a little easier.
Pins – Locate the deck arms. Most mowers will have one at each of the four corners. The deck will be fixed to the deck arms with Cotter pins. (Some may have nuts and bolts) Remove the two front pins and the two rear pins.
Slide – The deck will be free to move forward, which allows you to remove the deck drive belt from the engine drive pulley. In some cases, you may have a cable to remove; this depends on the blade engage type.
Push – With all pins removed and belt off, just push the deck sideways and it will pop off the arm bushing mounts. Apply some grease when refitting. Hey, I make that sound easy!
Inspect – Go ahead and turn the deck over to inspect the blades and blade boss (blade attachment). It’s likely that the blades are damaged; if they are, replace them.
Bent – If your blades are bent or worn, now is the time to take care of them. Replacement blades are easy to fit when the deck is off.
Boss – When your blade hits something hard, the blade boss pins are designed to break; this saves damaging more expensive components.
Replace – Check washers and bolts for damage. Blade bolts and washers are specially designed, so only use the original kit.
Remove – Remove plastic protection covers.
Pulley – Remove the drive belt tension assembly.
Key – Remove and store the key and the spacer ring safely.
Remove – Remove the timed belt protective cover.
Belt – Remove the broken belt, and check for damage.
Loosen – Loosen both pulley bolts; the bolts are positioned on the underside of the pulley.
Remove – Remove the two guide bolts. Remember to fit these after fitting the belt, but tighten them last.
Loosen – Loosen the two guide bolts.
Loosen – Loosen the lock-nut on the adjusting bolt, and thread it all the way out.
Push – Now push the tensioning assembly in all the way so it hits the adjusting bolt.
Set to 90° – Set the deck blades at 90° to each other.
Mark – Now mark the two main blade pulleys and the deck body as per the picture. Marking them with paint gives us a clear reference point when fitting the new belt.
Align – Keep your paint marks aligned and fit the belt to the tension assembly last.
Check – Check your paint marks again; it’s OK if you’re out by one or two teeth.
Routing – This is a typical timed belt routing.
Adjust – Adjust belt tension first, and tighten down the lock-nut. Do not tighten pulley bolts or guide bolts at this stage.
Check – Check belt tension as you adjust. Leave some play in the belt; it should deflect by about 1/2″ at its longest run.
Check 90° – Check that the blades are at 90 degrees. If all is OK, go ahead and fit the guide bolts, but don’t tighten them yet. Tighten the two pulley bolts, and now tighten the four guides.
Rebuild covers and fit the deck in reverse order; that wasn’t so bad!
Related Questions
Why does my deck belt keep breaking? Common reasons new belts keep breaking:
Why does my mower deck shake? Mower decks commonly shake because:
- Engine not at the correct rpm
- Engine not running correctly
- Blades damaged
- Deck belt damaged or worn
- Spindle bearing damaged or broken
As you’re a MacGyver type, you’ll likely find the Riding mower troubleshooting and the Video repair library useful.
Hey, I’m John, and I’m a Red Seal Qualified Service Technician with over twenty-five years experience.
I’ve worked on all types of mechanical equipment, from cars to grass machinery, and this site is where I share fluff-free hacks, tips, and insider know-how.
And the best part. it’s free!
Riding Lawn Mower Blades Won’t Engage — How to Fix, Causes, and
If you buy something through our posts, we may get a small commission. Read more here.
It can be frustrating when your riding lawn mower blades won’t engage after powering it on. This won’t only make your day’s work difficult but ruin your other engagements and turn your work session into repair. Several factors can cause your lawn mower’s blades not to turn on. But how can you fix this issue? Our professional team has come up with solutions to try.
Riding Lawn Mower Blades Won’t Engage
Taking care of the lawn is made easy with a riding lawnmower. Like every other machine, you don’t expect it not to develop faults. From the belt to the battery, things can cause the riding lawn mower blades not to engage even when the mower blades are fully sharpened. When these problems arise, our technical expert advises that you should do the following.
Refer to Manual from Manufacturer
One of the first things to do when you discover that your mower’s blades won’t engage is to refer to the manufacturer’s manual. Lawnmowers differ from manufacturer to manufacturers, so as their manuals. You won’t expect a Craftsman mower manual to be exactly the same with Husqvarna, Cub Cadet, or Ryobi. For this reason, you must refer to the manual whenever the blades won’t turn or if you notice any fault.
Inspect Belt
One of the reasons why the blades on your newly purchased Troy Bilt lawnmower may not engage is the belt. It’s either stretched or too loose, worn-out, or damaged, causing it to fall off easily. It could also snap out of position, especially if you tried to cut more grasses at a time that’s beyond its capacity.
The deck belt, located under the operator’s seat, works by engaging and disengaging the mower’s blade. The belt runs through a pulley system and spins the blades. If it has become damaged, the blades won’t engage.
Before carrying out any replacement, you should inspect the belt first in case your Cub Cadet mower has belt that keeps coming off. The configuration depends on the model and manufacturer, but most lawn mowers have the same design. Reduce the deck to its lowest setting and check out if it’s damaged or has accumulated grasses.
The belt must be inspected at least every six months. This way, you won’t be surprised and frustrated when you want to take care of the lawn.
Replace Belt, Cables, or Clutches
If you notice any damage or excessive wear on the belt during the inspection, it is advisable to address the issue by replacing it. Similarly, if the belt appears loose or excessively stretched, it is recommended to return it to ensure optimal performance.
If the blades don’t still work even after replacing the belt, you should check the blade cable. The cable is made up of metal with cast metal ends, a plastic sheath, and a bracket. If the metal ends are damaged or the cable gets kinked, you should replace it immediately.
You can do the same to the clutches if you find any of the parts damaged. Lawnmowers have clutches that shut off the blades while the engine is running. This part can wear out over time, and when they do, they won’t be able to power the blades.
It’s necessary that you inspect them for proper diagnosis. Disassemble the mower to monitor the clutch better.
If any of the parts that make up the clutches develops a fault, the blades won’t engage. It means you should replace them.
Check Pulley
The pulley could be another reason why the riding lawn mower is having issues causing the blades not to engage. The mower’s pulley controls the tension in the drive belt, which in turn turns the blades. If the pulley freezes and doesn’t rotate, the blades won’t engage.
This is why you need to check the pulley to know its state. If it’s frozen, then you should replace it. You should also investigate if other pulleys on the deck are okay [1].
Check Power Source/ Battery
Lawnmowers use the PTO (Power Takeoff) clutch mechanism to engage the blades. PTOs are either manually operated or electric. Batteries run the electric PTOs.
If the battery has a weak charge or is dead, it won’t power the blades. So, if the blades refuse to engage after powering it on, ensure that you check the battery. You must fully charge the lawn mower battery, and if it’s faulty, you should replace it with a new one.
Tips and Reminders
Here are some tips and reminders you must have at the back of your mind when engaging the mower blades.
- Check if the deck belt is installed properly.
- Make sure that you charge the battery fully if the mower blades are electrically powered.
- Ensure the deck is lowered to the desired height before starting it.
- Allow the engine to warm up for a few minutes before using it. Replace all damaged belts, cables, and clutches after inspection.
Why won’t my riding mower blades engage?
Even if you have a reverse threaded mower blade, your riding mower blades won’t still engage if the clutches are broken and the cable is damaged. Additionally, if the deck belt is damaged, the pulley system is frozen, and the battery has a weak charge, the chances are that your riding mower blades won’t engage.
How do you engage the blades on a riding lawn mower?
To engage the blades on a riding lawn mower that’s manually operated, turn the key clockwise to power it on, increase the throttle to half speed, and allow the engine to warm up for two minutes.
Then, lower the mower to the preferred cutting height. Push the lever to the right of the steering to engage the blades.
It’s the same if you want to engage a lawnmower with electric blades, except that you don’t have to push the lever to the right of the steering to engage the blades. Just pull up on the yellow Power Takeoff switch to the right of steering.
Conclusion
Lawnmower blades are liable to damages, so it’s typical for them to have issues. However, the level of damages depends on how often you use the mower. This is why carrying out periodic inspections is necessary to prevent escalating the damages. With these practical solutions explained, you can fix the issue that arises.
If you are unable to fix them, contact a professional or if warranty still covers your lawnmower, contact the brand’s customer service. Some manufacturers that have good customer support include Husqvarna, Craftsman, Cub Cadet. and John Deere.
The Best Zero-Turn Mowers of 2023
These achieve the rare feat of making lawn mowing fun.
By Roy Berendsohn Published: Mar 1, 2023
When it comes to yard work, zero turn mowers do the impossible. They make lawn mowing fun. They accomplish this by putting unprecedented speed, control and maneuverability at the disposal of the person mowing the lawn. The so-called “zero turn” feature of these mowers converts a grass cutting machine into something akin to an amusement park ride. You steer the machine with two levers—the left lever controls the left wheel, the right lever the right wheel. With that steering setup, you can zoom over the landscape cutting straight lines, curves, or pivot the mower into and out of a corner. What’s not to like?
Read on to understand how these agile grass cutters work, how we go about testing them, and see some candidates that we’ve recently tested as well as some that we haven’t but that we think look particularly promising.
How Zero-Turn Mowers Work
A zero-turn riding mower consists of an operator platform, a frame and wheels, an engine (or battery bank), transmissions (or motors), and a pair of control levers commonly known as lap bars. In gas mowers, the engine powers a pulley system. One group of pulleys drives the blades, another group powers a pair of transmissions–one at each rear wheel. When you move the lap bar forward or back, you are directing the transmission to go faster, slower, or even turn the opposite way. When one drive wheel turns clockwise and the other counter clockwise, the mower pivots. When the wheels rotate at different rates, the mower turns in an arc-shaped path. When the lap bars are in the neutral position, the mower stops. Aside from a parking brake, there’s no other braking mechanism. Battery-powered zero-turn mowers work the same way, but have separate motors to drive the rear wheels and one for each blade inside the mower deck.
When it comes to transmission, most mowers have a Hydrogear EZT—a well-known and cost-effective residential-grade transaxle with a reputation for durability.
Some mowers use a deck stamped from one piece of steel, others use a deck fabricated from multiple pieces and welded together. A fabricated deck can be built from thicker steel at a lower cost than it would be able to be built otherwise. Once you’re talking about stamping metal as thick as 10 gauge (about 1⁄8 inch thick), the cost of stamping such a deck would push up the mower’s price beyond what most people are willing to pay. The decks in the mowers below range from 42 to 52 inches, a typical size in this class of product. When powered by these engines and the Hydrogear, these mowers will deliver a decent cut quality at their rated top speed of 7 mph. Note, however, that cut quality declines steeply if you maintain that speed in very thick grass or on uneven terrain.
As to the electric mowers, they represent the leading edge of the technology in this category. These are remarkable and expensive mowers powered by large-voltage lithium-ion batteries. If you’re interested in reducing mowing noise and simplifying your maintenance routine by eliminating gas and oil, they’re worth a look.
Selecting a Zero-Turn Mower
Everyone would like to select the biggest possible zero-turn mower with the hope of whittling a big grass cutting job down to size as quickly as possible. Reality usually intercedes because these machines are expensive and the wide range of options available today quickly drive up the cost. Roughly speaking, you start somewhere in the range of a mower with a 42-inch deck costing in the vicinity of 3200 to 3500 and move up in increments of 1000 to 1500 until you reach entry-level commercial-grade equipment that costs 7000 to 8000.
Again, speaking in terms of approximation, a mower with a 42-inch deck will cut a two-acre lot (that takes into account that the house, driveway, outbuildings and various landscape features are taking up some of that space). Use a mower with a larger deck to cut anything over two acres. But here’s the caveat. That entry-level ZTR mower (3200, say) with a 42-inch deck will wear out faster and need more maintenance than a mower with a 50-inch deck, a heavier frame, larger engine and higher quality transmissions, and thicker deck with more robust blade spindles, costing 4500.
How To DIY: Craftsman LT1000 Lawn Mower. Deck Removal and Pulley Replacement.
In the simplest possible terms, you can cut a smaller area with a larger mower and expect more longevity out of the machine (not to mention a nicer mowing experience) or you can cut a larger area with a smaller machine and encounter more maintenance and a mowing experience that will be, we might say, a bit more rugged.
But there are still other factors to consider, in selecting a mower other than deck size and your budget. Larger mowers take more space in a garage or outbuilding. And a mower with a 50-inch or even 60-inch deck, as useful as it might be in getting the job done more quickly, may not fit through a fence’s gate, and it might be more difficult to maneuver in tight spots without creating scalp marks on the lawn from a lot of close-quarter pivoting.
Carefully consider all these factors when shopping for a mower: your budget, maintenance and whether you will perform that work yourself, mowing speed and time, maneuverability and trimming in tight areas, the importance that you place on your comfort while mowing, cut quality, longevity, storage, and access to the landscape.
How We Select and Test
There’s only one way to test a mower, and that’s to cut grass with it. But we also do more than mow.
We raise and lower the deck and adjust the seat. We look at service point access (the air filter, the spark plug, and the oil filter) and how easy it is to remove the deck. We mow approximately an acre with each mower, considering cut and mulching quality while running uphill, downhill, across washboard, and along sidehills. (On sidehills, we’ll mow surfaces pitched up to approximately 20 degrees; manufacturers generally recommend not going steeper than 10 degrees, but we like to be thorough.) We evaluate power and speed relative to cut quality—we investigate whether the mower delivers a decent cut mowing at full speed. When mowing in damp conditions, we look at whether the mower’s tires accumulate grass and how effectively it discharges moist clippings. Finally, we test maneuverability (these machines are, generally, very nimble) and how readily they come to a stop when you back off the lap bar control levers.
Why My Lawn Mower Blade Not Spinning Fast?
The grass-cutting experience can be spoiled if you realize the blades aren’t spinning as quickly as they should be. Not only would the slowly spinning blade waste your time, but it will also give your lawn an odd appearance.
There could be numerous reasons why the blades of your lawnmower are not spinning fast. Some of these include a seized pulley, a damaged deck belt, a damaged blade, a faulty safety switch, a dirty deck, or a poorly performing engine.
Read on to know more about lawn mower blade not spinning fast.
How Fast Do Mower Blades Spin?
Safety standards prohibit lawn mower blade speeds of more than 219 miles per hour. Common lawn mower blade speeds are close to 200 miles per hour.
Mower revolutions per minute (RPMs) are not governed by law, however usually operate at a rate of 2,600 to 2,900 when mowing grass. This equates to a rate of 43 to 48 revolutions per second for the typical lawnmower blade.
The American National Standards Institute (ANSI) specifies maximum allowable blade rotational velocities. Their rules state that the maximum allowable rotational speed for the blade’s tip is 19 thousand feet per minute, or around 219 miles per hour.
Lawn Mower Blade Not Spinning Fast: Reasons And Fixes
Various issues can make a lawnmower blade not to spin fast. here is a quick table of the potential causes of this problem and easy fix.
| Potential Causes | Solution |
| Damaged Belt issue | Replace damaged belt |
| Damaged Blade | Remove damaged blade |
| Bad safety switch | Fix bad safety switch |
| Dirty Mower Deck | Use silicone spray, remove dirt from mower deck |
| Seized pulley | Replace the pulley |
Damaged Belt Issue
When a belt is overstretched or worn, it might slip, preventing the blades from turning or making them turn very slowly. This occurs frequently because belts wear out and need to be replaced since they stretch.
Your lawnmower’s belt is wound around the spindle and idler pulleys, and is driven by the drive shaft pulley. If the pulley on a spindle becomes stuck due to a seized shaft, the belt will eventually break.
The Fix
- Check deck belt and PTO belt for side wear. Check the bearings on the spindles to see if they are getting worn.
- Lower the deck to its lowest position and remove the drive pulley belt protector to replace the belt.
- Loosen the belt from the pulley, front deck attachment point, and PTO cable pin, then pull back to remove the spring.
- Remove the blade spindle covers and loosen the idler pulley bolts to take the belt off between pulley and belt guard. If the belt breaks completely, ensure sure all pulleys spin freely to avoid a second break.
The Blade Might Be Damaged
Even while mower blades are quite durable, they can be damaged. If the blade is damaged, when engaged, the blades will not spin fast.
The Fix
Check the mower blade for any damage. To inspect the mower blade from every angle, take it off the mower. This allows you to inspect the blade from all angles and in good light, allowing you to spot even the smallest of nicks or kinks.
It is also important to check that the blade has been mounted correctly, as an improperly installed blade will slow down the cutting speed of the mower.
Bad Safety Switch
If the safety switch fails, the mower blades will not function. Blades will typically stop rotating or slow down considerably if any of many safety switches on a typical lawn mower are tripped.
The Fix
If your mower’s blades do not rotate or spin quickly, and you have checked out all other potential causes, check the electrical contacts in the safety switches to verify they are not being triggered unnecessarily.
These switches safeguard the operator and others around the machine, so don’t turn them off.
Dirty Mower Deck
The cut quality or the blade rotation speed of your lawn mower may be affected if grass accumulates underneath the deck.
Even though scraping the deck to get rid of trash may be a hassle, it’s essential if you want a clean lawn. A blocked deck can also increase the workload on your mower’s engine.
The Fix
Use a silicone spray to prevent dirt and grime from clinging to your deck. The accumulation of grass under the deck can also be reduced by avoiding mowing it when it’s rainy and by cutting it more frequently.
Seized Pulley
When a pulley becomes stuck, it prevents the belt from spinning and preventing the belt from moving.
A belt can shift, start smoking, and eventually break because of this.
The Fix
- First, with the drive belt disconnected from the engine pulley, engage the blades by lifting the lever.
- Manually turn the spindles and pulleys, the deck lever must be engaged to disengage the brakes.
- Make sure no pulleys are making a growling noise, and then check to see if any of them feel too snug. This indicates that the pulley needs to be replaced.
Damaged/bent lawnmower blades, a weak spring, a broken shear pin in the drive pulley, poor electrical connection or poor engine performance may also cause your lawnmower blade not to spin fast.
How Do I Make the Blade Spin Faster on My Lawnmower?
Lawn mower blade speed should never be increased. Lawn mower blade speeds are optimized for safety.
You won’t get a better cut or mow faster with a faster blade speed. Increased horsepower would speed blades through thick, heavy grass.
However, increasing blade speed stresses the blade, deck, and drive system, increasing the risk of damage. it will also cause vibration which will dislodge nuts, bolts, and the mower’s engine.
But if you determine why your mower’s blade is not spinning fast, the first step is to address the previously identified issues.
However, there are, a few methods or modification for increasing the speed of your mower’s blade depending on the type of mower.
Belt Drive Mowers and Adjustable Blade Speed
It is most straightforward to increase the blade speed of a mower with a belt drive and horizontal blades by increasing the engine speed. The blades on such mowers cease spinning whenever the engine is running since there are no gears to separate the two. Such is the case with many earlier models of walk-behind mowers.
Increasing the mower’s engine RPM will result in a faster-spinning blade on a gearless, belt-driven mower.
Adjustable Gear-Operated mower System
Geared walk-behind mowers, can have their RPM increased. A blade belt clutch (BBC) is a device that allows the engine to keep running even when the blades are stationary.
The BBC cable, located under a panel above mower deck, is used to adjust blade speed. Unscrew the BBC cable bolts and adjust it to increase RPM. To speed up or slow down blades, pull or slacken the cable.
Blade Speed Increase on Belt and Pully Mowers
Belt-and-pulley riding mowers can spin blades faster. Replace your blade pulley and drive pulley with smaller and larger ones, respectively. The mower’s cutting quality may suffer if the blades spin quicker.
How to Check Blade Speed on Your Mower?
If your mower blades seem slow, look at the grass after cutting it.
If your blades are too slow, you’ll end up tearing and damaging the grass instead of cutting it. Yet, having excessively fast blades is not only dangerous, but also inefficient.
There should be information about the engine and blade speed in the mower’s manual.
A tachometer can be used to monitor the engine speed of your lawnmower.
It’s better to have a professional mechanic take a look at your mower in cases like this because the problem is almost certainly mechanical.
Maintaining a beautiful lawn can be a daunting task, especially if you lack the appropriate know-how and tools to handle the challenges that may crop up. Fortunately, LawnAsk is here to offer you an all-encompassing resource that covers everything you need to know about lawn care.
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