Lawn mower cylinder head. 2023. Lawn Mower Failure to Start for Head Gasket–…

23. Lawn Mower Failure to Start for Head Gasket– The Symptoms, Causes Solutions

The head gasket is a fundamental part of a gasoline-powered lawnmower engine. It seals or separates the cylinder head from the engine block to prevent the mixture of coolant and oil. Also, it can seal in the internal combustion process. A faulty or blown head gasket may cause engine failure. With these role-playing

Table of Contents

So, how do identify why the Lawn Mower Failure to Start and repair if the lawnmower has a blown head gasket? You may see different changes if it doesn’t work properly. These are oil leaks, coolant consumption, blue or white smoke, and starting failure. Once these symptoms appear, you must change the head gasket or call the experts.

The discussion below will discuss the possible causes, effects, and solutions to the head gasket that causes lawn mower engine failure. I hope it helps you in lawn mower troubleshooting.

What actually is the Head Gasket?

A head gasket plays a vital role in an internal combustion engine. It can seal or separate the engine block and cylinder head to avoid combining the engine fluids. Again, it can prevent any pressure losses, which is why the lawnmower works improperly. If any leak is available in the head gasket, the engine may run poorly or get overheated soon.

Manufacturers use multiple layers of steel (MLS) to make the modern gasket more durable. The center layer is thicker, whereas two thinner outer layers can resist extreme heat and chemical reactions. Earlier, people used to use fiber head gaskets. But they were more prone to failure. But MLS gaskets are relatively more efficient and long-lasting.

Let’s talk about the problems and vice versa about the head gasket:

The Lawn Mower Failure to Start after replacing the head gasket

You have changed the head gasket thinking everything will be fine. But it is not happening as the lawnmower is not even starting properly. The main reason it is happening is installing an incompatible or faulty head gasket. Also, you may haven’t installed it properly, or something is wrong, which you shouldn’t do.

If the lawn mower failure to start after replacing the head gasket, possibly the gasket itself is the reason. You should ensure that it is properly seated. Also, there should be no leaks. If the problem persists, it may be necessary to replace the cylinder head.

Another reason can be the fouled or damaged spark plug. It may not be firing in common ways. Check the gap on the spark plug and inspect the fuel line if it is clogged.

Sometimes pre-ignition can cause the replacement head gasket not to work well. If the engine combusts fuel very often in a single cycle of the engine, the cylinder head gets large pressure inside. Then, the engine starts working unwantedly, which may cause the head gasket failure.

Leaks of coolant from rusted or dodgy piping can be why the engine fails to start after replacing the head gasket. When it happens, the engine will get overheated, and the head gasket won’t control this.

How do I know if my lawnmower has a blown head gasket?

A lawnmower is like a magical device to maintain the lawn soothing our eyes. Its peak performance depends on several factors, and the head gasket is one of them.

Symptoms of a blown head gasket on a lawnmower

If the gasket is blown, you may see a lot of white smoke from the engine. Sometimes, the engine may fail to start, which signifies a damaged head gasket. When the gasket is worn out, it leads to low engine power.

There can be a leak of oil that may blow the gasket. You may run a compression test to diagnose a blown gasket. Also, you may use compression gauges to calculate the internal combustion pressure. For this, pull the started cord again and again. You may have a blown gasket if the combustion chamber pressure is lower than 60 psi even after adding little engine oil.

A cracked head gasket, loose or missing bolts, and compromised seals in the gasket can make the combustion chamber lose its vacuum seal. The released and sustained energy powers the pistons when gasoline is combusted in the chamber. But a blown gasket can cause reduced pressure and power from the combustion.

If you have an active lawn mower, all the head gasket seals are in the right shape. But the seals dry out after a certain time. Then, they become very brittle, and fluid leaks around the gasket. It is a symptom of a blown head gasket. You can temporarily fix the problem using a liquid sealant. But replacing the head gasket is the best solution.

When an engine overheats frequently, it may cause head gasket failure. On the other hand, a blown gasket seal can also cause the engine to overheat at the normal temperature. A blown tool can make passage for hot exhaust gases into the cooling system. Again, the coolant turns into steam when the gasket is blown and leaks the coolant toward the cylinders. As a result, the engine becomes hotter, and the lawn mower failure to start.

If you see milky sludge beneath the oil filler cap or on the dipstick, you can consider that the head gasket is compromised. The reason behind it is that the coolant leaks and mixes with oil. A replacement oil filter or engine oil flush can be a good solution.

You may follow the below steps too for knowing if the gasket is blown or not:

First, check out all the general symptoms which I have explained above.

Remove the engine cover and relevant items to access the engine properly.

Separate all the complementary parts available over the engine.

Cub Cadet Rescue with Briggs and Stratton blowing oil, bad head gasket, check compression release

Identify the sparkplug position and unscrew it.

Take the necessary tools and disassemble the head of the engine.

Find out all the scuffs, marks, or blows around the head.

Identify if there are any carbon deposits of valves and pistons.

Replace the gasket if it is blown; otherwise, reassemble the parts.

Turn on the engine and check out if the lawnmower is working properly.

Why is my lawnmower cranking and lawn mower failure to start?

Cranking is generally the turn and starter power of any lawnmower engine. Usually, the flywheel spins around when you try to start the engine.

There are several reasons why your lawn mower failure to start. Here are some of them:

A bad or no gas in the chamber is a reason for lawnmower failure. Maybe the gas is not fresh, or not enough gas in the chamber.

Plug wire is off or loose enough which leads to the engine not working well.

A faulty or wet plug can be why the engine fails to operate well.

Not enough charge in the battery, or you haven’t changed the battery for a long time.

You have forgotten to keep the air filter clean, which is also possible.

You should set the manual choke to full to start a cold engine; otherwise, the engine will fail.

You are not following a set procedure for the lock-out or safety sensors available in the mower.

lawn, mower, cylinder, head, 2023

Some kinds of faults in the control module and coil system.

A possible reason can be a fault in the engine compressor or valve sections.

How much does fixing a blown head gasket on a lawnmower cost?

If you are a beginner, you may need to spend 3-8 hours troubleshooting any head gasket of the engine. It includes the assembling and disassembling of the lawnmower engine. If you need to replace the gasket or other parts, it may require more money.

Average head gasket replacement requires 1620-1980. This cost includes the associated labor cost (around 900-1150) and buying new parts cost (720-830) on average.

The Head gasket of a lawnmower can keep the lawnmower at its peak performance. If the engine has a blown gasket, you should find out the reasons first. Then, repair the damaged part. Alternatively, replace the device for the best solution.

I have included all the reasons and signs of having a faulty or blown head gasket. You should prevent gasket failures which is better than curing them. After all, it will save you money and time together.

Check out our additional article:

There are a number of reasons, mechanical and otherwise, why a mower won’t run. The good news is that fixing most all of the issues is easy enough for a DIYer to handle.

By Tony Carrick and Manasa Reddigari | Updated Aug 8, 2022 4:03 PM

We may earn revenue from the products available on this page and participate in affiliate programs.

Lawn care can be tedious, but once the grass starts growing in the spring, mowing becomes a fact of life in most neighborhoods. When you finally muster the strength to tackle that first cut of the season, there are few sounds as disheartening as that of a lawn mower engine that turns over but doesn’t start.

Before you drag the mower in for repairs or invest in costly replacement parts, first make sure that a clogged air filter, soiled spark plug, damaged safety cable, clogged mowing deck, or contaminated gas isn’t to blame. Work through the following steps, and you may be able to get your puttering grass guzzler up and running again in no time.

A lawn mower repair professional can help. Get free, no-commitment repair estimates from pros near you.

Change the lawn mower carburetor filter.

Your lawn mower’s air filter guards the carburetor and engine from debris like grass clippings and dirt. When the air filter becomes clogged or too dirty, it can prevent the engine from starting. To keep this from happening, replace paper filters—or clean or replace foam filters—after every 25 hours of engine use.

The process for removing the filter depends on whether you are operating a riding or walk-behind lawn mower. For a riding mower, turn off the engine and engage the parking brake; for a walk-behind mower, pull the spark plug wire from the plug. Then, lift the filter from its housing.

The only choice for paper filters is replacement. If you’re cleaning a foam filter, wash it in a solution of hot water and detergent to loosen grime. Allow it to dry completely, and then wipe fresh motor oil over the filter, replace it in its housing, and power up the mower—this time to the pleasant whirring of an engine in tip-top condition.

Check the spark plug.

Is your lawn mower still being stubborn? The culprit may be the spark plug, which is responsible for creating the spark that ignites the fuel in the engine. If it’s loosened, disconnected, or coated in water or carbon residue, the spark plug may be the cause of your machine’s malfunction.

Locate the spark plug, often found on the front of the mower, and disconnect the spark plug wire, revealing the plug beneath. Use a socket wrench to unscrew the spark plug and remove it.

Check the electrode and insulator. If you see buildup, spray brake cleaner onto the plug, and let it soak for several minutes before wiping it with a clean cloth. Reinstall the spark plug, first by hand, and then with a socket wrench for a final tightening. If the problem persists, consider changing the spark plug.

Clear the mower deck of debris.

The mower’s deck prevents grass clippings from showering into the air like confetti, but it also creates a place for them to collect. Grass clippings can clog the mower deck, especially while mowing a wet lawn, preventing the blade from turning.

If the starter rope seems stuck or is difficult to pull, then it’s probably due to a clogged deck. With the mower safely turned off, tip it over onto its side and examine the underbelly. If there are large clumps of cut grass caught between the blade and deck, use a trowel to scrape these clippings free. When the deck is clean again, set the mower back on its feet and start it up.

Clear the vent in the lawn mower fuel cap.

The mower started just fine, you’ve made the first few passes, then all of a sudden the mower quits. You pull the cord a few times, but the engine just sputters and dies. What’s happening? It could have something to do with the fuel cap. Most mowers have a vented fuel cap. This vent is intended to release pressure, allowing fuel to flow from the tank to the carburetor. Without the vent, the gas fumes inside the tank begin to build up, creating a vacuum that eventually becomes so strong that it stops the flow of fuel.

To find out if this is the problem, remove the gas cap to break the vacuum, then reattach it. The mower should start right up. But if the lawn mower won’t stay running and cuts off again after 10 minutes or so, you’ll need to get a new gas cap.

Clean and refill the lawn mower fuel tank.

An obvious—and often overlooked—reason your mower may not be starting is that the tank is empty or contains gas that is either old or contaminated with excess moisture and dirt. If your gas is more than a month old, use an oil siphon pump to drain it from the tank.

(It’s important to be careful as spilled oil can cause smoking, but there are other reasons this might happen. Read more about what to do when your lawn mower is smoking.)

Add fuel stabilizer to the tank.

Fill the tank with fresh fuel and a fuel stabilizer to extend the life of the gas and prevent future buildup. A clogged fuel filter is another possible reason for a lawn mower not to start. When the filter is clogged, the engine can’t access the gas that makes the system go. If your mower has a fuel filter (not all do), check to make sure it’s functioning properly.

First, remove the fuel line at the carburetor. Gas should flow out. If it doesn’t, confirm that the fuel shutoff valve isn’t accidentally closed. Then remove the fuel line that’s ahead of the fuel filter inlet. If gas runs out freely, there’s a problem with the fuel filter. Consult your owner’s manual for instructions on replacing the filter and reassembling the mower.

Inspect the safety release mechanism cable.

Your lawn mower’s reluctance to start may have nothing to do with the engine at all but rather with one of the mower’s safety features: the dead man’s control. This colorfully named safety bar must be held in place by the operator for the engine to start or run. When the bar is released, the engine stops. While this mechanism cuts down on the likelihood of horrific lawn mower accidents, it also can be the reason the mower won’t start.

lawn, mower, cylinder, head, 2023

The safety bar of a dead man’s control is attached to a metal cable that connects to the engine’s ignition coil, which is responsible for sending current to the spark plug. If your lawn mower’s engine won’t start, check to see if that cable is damaged or broken. If it is, you’ll need to replace it before the mower will start.

Fortunately, replacing a broken control cable is an easy job. You may, however, have to wait a few days to get the part. Jot down the serial number of your lawn mower, then head to the manufacturer’s website to order a new cable.

Check to see if the flywheel brake is fully engaged.

The flywheel helps to make the engine work smoothly through inertia. When it isn’t working properly, it will prevent the mower’s engine from working.

If it is fully engaged, it can make a mower’s pull cord hard to pull. Check the brake pad to see if it makes full contact with the flywheel and that there isn’t anything jamming the blade so the control lever can move freely.

If the flywheel brake’s key sheared, the mower may have run over something that got tangled in the blade. It is possible to replace a flywheel key, but it does require taking apart the mower.

Look out for signs that the mower needs professional repairs.

While repairing lawn mowers can be a DIY job, there are times when it can be best to ask a professional to help repair a lawn mower. If you’ve done all of the proper mower maintenance that is recommended by the manufacturer, and gone through all of the possible ways to fix the mower from the steps above, then it may be best to call a pro. Here are a few signs that indicate when a pro’s help is a good idea.

  • You see black smoke. The engine will benefit from a technician’s evaluation, as it could be cracked or something else might be worn out.
  • Excessive oil or gas usage. If you’ve changed the spark plugs, and done all of the other maintenance tasks, and the mower is consuming more than its usual amount of oil or gas, consult a professional for an evaluation.
  • The lawn mower is making a knocking sound. When a lawn mower starts making a knocking sound, something could be bent or out of alignment. It may be tough to figure this out on your own, so a pro could help.
  • A vibrating or shaking lawn mower can be a sign of a problem beyond a DIY fix. Usually something is loose or not aligning properly.

How to Tell If Lawn Mower Engine or Head Gasket is Blown (11 Signs)

Whether you have a simple small engine on your push mower or a water-cooled engine on your riding lawn mower, you might run into an issue with your head gasket. Depending on your engine’s design, some of the symptoms might be different, but several of them will be the same. So, if your lawn mower isn’t running like normal and your usual fixes aren’t working, let’s look at the head gasket and see if that’s where the problem lies.

How to Diagnose a Blown Lawn Mower Engine or Head Gasket

A head gasket seals the head to the engine block and needs to do two main jobs. First, it keeps fluids within their required locations, and second, it holds compression within the cylinder. As soon as a head gasket breaks, you’ll experience the following issues.

How to Tell If Your Lawn Mower Engine is Blown (5 Symptoms)

If your lawn mower has an issue with the head gasket, you’ll experience several symptoms. Here are some signs you might run into if your lawn mower has a blown engine.

Lack of Power

The first thing you’ll probably notice if your head gasket is on its way out is a loss of power. The pressure created from the combustion process to move the piston can escape when the gasket has issues and reduces the engine’s power. Depending on where your head gasket is, the signs can be different.


The next symptom you might experience is that your lawn mower will overheat. Your lawn mower overheats because it has to work much harder due to the lack of power. Also, if the gasket is blown between the oil passages and the coolant passage, both fluids will get contaminated, and won’t be able to perform as intended.

Rough Performance

Now, if you add a lack of power and overheating together, you end up with a lawn mower engine that runs rough. So, if your lawn mower is noticeably struggling, like with surging RPMs, you could be looking at a blown head gasket.

Trouble Starting Your Lawn Mower

Next on the list of symptoms is trouble starting your lawn mower. Usually, you would probably look at the usual suspects like a dirty carburetor, a dirty spark plug, or maybe an old fuel filter. But if all of these components look okay, knowing where else to look can be confusing. Well, the head gasket could be your issue.

I’m pretty sure that most of the lawn mowers you see sitting on the side of the road for trash collection have a blown head gasket. So, knowing what to look out for might keep your lawn mower out of the mower graveyard.

Trouble Keeping Your Lawn Mower Running

Last on my list of signs of a blown lawn mower engine is trouble keeping your lawn mower running. Stalling becomes a real problem once a head gasket starts to go bad and when it has totally blown. This can be down to a number of reasons depending on the design of your engine.

For example, you might have oil or coolant in the combustion chamber, making ignition difficult, overheating is definitely going to make your lawn mower stall, and finally, you might have a complete loss of compression preventing your mower from running.

Signs of a Blown Head Gasket (6 Signs)

Now that you have a good idea of the problems a blown gasket can cause, let’s go over how to tell if a lawn mower engine is blown. There are a bunch of different telltale signs that will confirm your head gasket is at fault. Here’s what to look out for and some tests you can run.

Whooshing Sound

If you have a lawn mower blown head gasket, then you might be able to hear where it is blown. If the gasket is blown from the cylinder to the outside of the head, then the pressure in the cylinder head will be able to escape.

So, you might hear a whooshing sound as air escapes while the pistons move up and down. Sometimes you can actually feel the air leaking if you place your hand close to the gasket. Be careful of the moving parts and the hot engine if you try this test.

Leaking Oil from the Head Gasket

Another pretty common sign is oil leaking from between the head and the engine block. This is where the engine compression pushes oil out of the blown gasket. So, inspect your lawn mower where the head meets the block and see if you have a noticeable leak.

Oil Smoke from the Exhaust Pipe

Inside your engine, there might be oil ports that allow oil to travel around the engine. So, if the gasket is blown between the cylinder port and one of the oil passages, then the oil might get into the combustion chamber. You’ll notice smokey exhaust if there is an internal break in the head gasket.

Oil Air in the Coolant

If you have a water-cooled engine, like a John Deere tractor mower, then water runs through the engine to regulate the engine temperature. If the gasket is broken between these two parts of the engine, you’ll end up with air and oil in the water-cooling system.

A quick way to check is to look at the top of the water radiator or reservoir. If you find oil floating on top of the water, then your gasket is at fault. Another sign is seeing bubbles when checking the tops of the radiator or the water reservoir. Bubbles happen when the engine forces air from the cylinder head into the cooling system.

Oil Coolant in the Cylinder Head

You also want to look inside the cylinder head when figuring out how to tell if the lawn mower engine is blown. The easiest way to check the cylinder head is to remove the spark plug and look inside the engine. If you find oil or coolant inside the head, you’re more than likely dealing with a break in the gasket.

Loss of Compression

If you have been through the lawn mower blown head gasket symptoms and discovered a few signs, then you can confirm this by conducting a compression test to see if the lawn mower’s head can hold a specific amount of air pressure without leaking. You can test the air pressure by removing the spark plug and connecting a pressure gauge. Then, start the engine by using the starter pull cord or the electric starter and test the pressure. If the pressure is below the desired reading or reduces over time, the cylinder head has a leak.

However, bad results could also signify problems like a worn-out cylinder or worn-out piston rings. This test only confirms a compression problem but doesn’t specifically single out the head gasket. So, you’ll need to do more investigating.

Inspecting a Lawn Mower Blown Head Gasket

By far, the best way to confirm you have a blown head gasket is to conduct a visual inspection. If you have been through all the lawn mower blown head gasket symptoms and done the tests, then the final step is to inspect the actual gasket.

Now, this is a pretty lengthy job because you have to strip down the lawn mower engine. With some lawn mowers, this is pretty straightforward, but more complex engines require more work. You’ll probably have to remove the exhaust pipe, carburetor, valve cover, push rods, cooling system, and the actual head to get to the lawn mower blown head gasket. But with some patience and a handful of tools, it’s not too difficult.

Is There Anything You Can Do in Either Case?

I know that stripping down an engine might sound like a lot of work. So is there anything you can do instead? Well, this all depends on how the head gasket is broken. If it’s damaged internally, say between the cylinder and one of the oil/coolant passages, then, unfortunately, you need to replace the gasket.

There are products you can flush through a water cooler mower engine to repair a leak, but I’ve never heard of anyone having much success, especially long-term.

Now, if the break is from the cylinder straight to the outside of the engine, then you might be able to do a temporary fix. You’ll find products that can seal a gasket from the outside to block the air from escaping. But again, this is only a temporary fix. My best advice is to grab a new gasket and carry out a long-term fix.

What Causes a Blown Head Gasket on a Lawn Mower?

General wear and tear is the main reason why head gaskets blow. But there are a few things you can avoid to ensure your gasket doesn’t break. Overheating is one of the main causes of a head gasket’s early failure.

So, make sure to use the right lawn mower oil type, keep your oil topped off, perform regular oil changes, and keep the cooling systems in tip-top shape, including cleaning the cooling fins on the top of the flywheel and the water-cooling system.

About Tom Greene

I’ve always had a keen interest in lawn care as long as I can remember. Friends used to call me the lawn mower guru (hence the site name), but I’m anything but. I just enjoy cutting my lawn and spending time outdoors. I also love the well-deserved doughnuts and coffee afterward!

Leave a Reply Cancel reply

Copyright © 2010. 2023, All Rights Reserved.

Affiliate disclosure: As an Amazon Associate, we may earn commissions from qualifying purchases from You can learn more about this here.

Is It Hard To Change Mower Gasket? Here’s what you need to know

Head gasket failure is common, especially in hard-working older mowers. I’m a mechanic for over twenty years and I’ve replaced a ton of them. Mowers aren’t complex, most repairs including gasket replacement are possible with just a little knowledge, and this post covers it all.

A mower head gasket is not difficult to replace. However you will require a torque wrench to tighten the cylinder head to the correct specification, this procedure is crucial to successful head gasket replacement. To replace a mower head gasket you’ll need to remove some components, they include:

changing a head gasket on a pulsar push mower 200 cc motor

In this post, you’ll learn how easy it is to replace your mower head gasket and how to use a torque wrench. Before working on your mower, always remove the plug wire to prevent accidental starting.

Tools You’ll Need To Replace Mower Head Gasket

To successfully replace the head gasket you’ll need the following tools:

  • Wrench set
  • Ratchet socket set
  • Screwdriver set
  • Pliers (long nose best)
  • Torque wrench (used to tighten cylinder head)
  • Feeler gauge (used to set valve lash)
  • Plastic scraper tool (used to clean cylinder head)

You’ll need the following supplies also:

Remove Mower Blower Pull Assembly

Begin by removing the pull assembly. We need to remove the pull assembly as it allows us to access the cylinder head.

The pull assembly is as its name suggests the assembly that houses the pull cord and recoil. Some mowers will use one-piece assembly (blower housing) others employ a two-piece. Several fasteners (four usually) removes the complete assembly.

Remove Mower Carburetor

Remove the carburetor by first removing the air filter. You’ll also need to clamp the gas line or drain down the gas tank.

With the air filter removed, and the gas line clamped, go ahead and remove the fuel line.

A couple of fasteners hold the carburetor to the engine, when you remove them the carburetor will be free.

Note where the carburetor gaskets are positioned and their orientation, replacing these incorrectly may cause the carburetor to make an ineffective seal and result in a surging engine. With the gaskets noted, unhook the throttle springs by turning the carburetor sideways. Set the carburetor aside and store it carefully.

Remove Mower Muffler

Some mowers may not require the muffler removed and if you can access the cylinder head bolts, feel free to leave the muffler in place.

If on the other hand, you need to remove it, use caution, muffler bolts often break when removing.

If you can, spray some WD40 to help reduce the risk of breaking. Two bolts are common and the bolts may employ a locking tab.

Remove Mower Valve Cover

The valve cover lives at the front of the engine and usually has OHV (Over Head Valve) embossed. To remove the cover you’ll need to remove four fasteners. Best to elevate the front of the mower engine, this helps prevent oil from flowing forward and out onto the mower deck.

Have a rag handy as there’ll be some oil spill. Set the valve cover and fasteners aside. Note also, the valve cover gasket may be damaged in the removal process, that’s just the way it goes. If that is the case you’ll need to replace the gasket or use a heat and oil-resistant silicone gasket, maker.

Remove Pushrods

Pushrods are metal rods used to push the rockers which open valves. The intake and exhaust rods may be different, note them before removing them.

To remove pushrods, depress the valve spring with your thumb and slide the rocker over the pushrod, freeing it. Note its location and orientation, as said, pushrods usually aren’t identical.

Remove Mower Head Bolts

The bolts (approx. six) are located on the cylinder head, some may be located behind the valve cover.

To remove the head, the head bolts must be loosened in a star sequence. Initially, each bolt is loosened by a quarter turn before moving to its opposing bolt. This prevents warping the cylinder head.

Remove The Mower Head

With all the bolts loosened and removed, you are now free to remove the cylinder head. You may need to loosen it by tapping it with a piece of timber, avoid prying with a lever, or tapping with a hammer.

Remove the head and set it aside carefully, alloy is a soft metal and will damage easily.

Cleaning Mower Head Block

To prepare for the new gasket, both surfaces will need to be cleaned. Old gasket material tends to stick to the surfaces. To clean them you’ll need to use a plastic scraper, avoid metal scraper or wire wheel.

lawn, mower, cylinder, head, 2023

Metal tools will damage the machined surface and could cause premature gasket failure. Cleaning can be tedious but a good scraper and some brake cleaner will clean it up in jig time.

Fitting New Mower Head Gasket

Fitting the new gasket is easy, most will only fit one way. Go ahead and fit the gasket to the engine, two dowels are employed to help locate the gasket and also the head.

Before fitting the cylinder head, clean the bolts using a wire brush but don’t oil them.

Lubing the bolts interferes with the torque measurements.

Mate the cylinder head with the block, be sure it seats correctly on the block dowels. Hand thread all the bolts into the head until they seat. At this point, we’ll need a torque wrench to nail the procedure correctly. It is not advisable to tighten without a torque wrench. Getting this part wrong risks warping the head and damaging the gasket.

Check out lawnmower head gaskets on the Amazon link below.

Using Torque Wrench To Tighten Mower Head

To use a torque wrench you’ll first need the cylinder head specs. Every engine make is different, so you’ll need to check yours. Torque specs are measured in ft. lbs. (Feet Pounds) in the USA and Nm (Newton Meters) Europe. Your torque wrench will have both measurements.

To set the wrench, first, loosen the lock then turn the handle to the desired measurement and tighten the lock again.

The torque wrench is now set to a specific torque setting and will give an audible click when it reaches that measurement.

If you need video help on setting a torque wrench, check out “Setting a torque wrench video” or I wrote a complete guide on buying and using a torque wrench, check out here “Best torque wrench for mower blades”.

When all head bolts are tightened by hand until seated, using a torque wrench and socket, tighten each bolt in a star pattern. Star pattern simply means tighten bolts in an opposing sequence (avoid tightening adjacent bolts sequentially).

Fit Push Rods

When tightened, the pushrods will need to be fitted, be sure you are fitting the correct rod.

Insert the rod into the block until it seats against the camshaft, now depress the valve spring using your thumb and slide the rocker onto the rod tip. Repeat for the second rod.

Ideally, valve clearance should be checked, it’s covered in the video library or check out this post “Mower engine valve adjustment” or check out the valve adjustment video here.

Reassemble now in reverse order, remember to replace the valve cover gasket, check and top up the oil if needed. Job done, that wasn’t so bad!

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!

Lawn Mower

Small engine vehicles are key for home and business owners. The better care you take of your lawnmower’s engine, the better your lawnmower is going to operate and perform. At Bar’s Leaks, we offer a wealth of lawnmower and small engine products — chemical tools owners can trust to deliver value.

What type of lawnmower issues are you experiencing? Do you have problems with a snowblower, or weed trimmer? For the best in small engine products, we have you covered. We’ve been leading the industry for decades when it comes to leak prevention and repair, and we talk to customers every week about how our products can be used in small engine applications. Read on to learn more.

Look for These Small Engine Issues

You probably know when your lawnmower needs some help. Are you constantly forced to top off oil levels in your small engine appliance? Do you notice blue smoke coming out of the exhaust, more so than is normal? Do you notice new leaks, or leaks that are increasing in size/quantity? These are all warning signs that your lawn mower is experiencing an engine-related issue. In many cases, the issue could be a leak. The bad news: the longer you wait to address it, the more costly and intensive it will be to repair. The good news: we’ve probably got you covered with quick, effective and affordable fix.

The Bar’s Leaks Advantage

What is the Bar’s Leaks advantage? It’s your ability to trust that our products represent the latest and greatest stop-leak and engine-repair solutions at the best possible value. For more than 70 years, the team at Bar’s Leaks has worked on perfecting its lawn mower engine products and lawn mower leak fix solutions. Care and attention to detail are poured into all products, which are designed and manufactured here in the United States.

One of the best parts of choosing products from Bar’s Leaks is that they represent a significant savings over physical repairs. Get the most value for your investment by selecting fast, effective, affordable lawnmower engine products from Bar’s Leaks.

Secure Effective Lawn Mower Solutions Now

Your lawnmower or small engine appliance is a tool that should help you keep your yard and other spaces as clean and well-maintained as possible. If and when you start experiencing issues with your small engine, don’t continue using it at less than its full potential. Get the solution you need at Bar’s Leaks. We offer guaranteed safe and easy-to-use products that require no specialized knowledge or experience. When you choose Bar’s Leaks, you’ll get results.

Visit a local store to find Bar’s Leaks products, or browse our online selection today.