Replacing the oil pump on the Partner 350 chainsaw

Oil pump malfunctions

Regardless of the manufacturer, any model of a chainsaw has problems in the lubrication system.

Chainsaw oil pump assembly

The nature of the lubrication system malfunctions can be different, and therefore, before starting the repair, it is necessary to accurately determine the cause of the oil leak or its failure to hit the tire. If we exclude the possibility of mechanical damage, then the following breakdowns of the lubrication system can be distinguished:

• Leaky connection of the line with the output channel of the chainsaw oil pump;
• Not tight fit of parts in the plunger system;
• Inconsistency between the parameters of the discharge chamber and the dimensions of the plunger;
• Lack of tightness of the oil line with the inlet union of the oil pump.

It is quite easy to eliminate oil leakage from a chainsaw if it is not used for a long time. This will require several screwdrivers and locksmith wrenches..

Chainsaw pump repair

There is an opinion that it is quite problematic to repair the oil pump of a chainsaw with your own hands. In fact, if you have basic locksmith skills and general concepts and rotating mechanisms, you can easily restore its original parameters. To do this, prepare the following tools and accessories:

• a set of curly and flat screwdrivers;
• open-end wrenches and socket heads;
• rags.

To eliminate pump malfunctions, it is necessary to dismantle it without touching the working part.

Installed oil pump on a chainsaw

A sealing gasket must be present between the two halves of the unit, which, in the presence of gusts and changes in height, will need to be replaced with a new one. The next step is to check the integrity of the supply hose. On its cylindrical generatrix there should be no diaper rash and cracks, which in the future can lead to a loss of tightness of the system. If such lines are identified, they need to be replaced, and a good hose should be rinsed and installed on a sealant to the ends of the tank and pump.

The outlet channels of the oil pump must not have foreign inclusions (dust, shavings, dirt). Such blockages can lead not only to a deterioration in the lubrication process and the formation of vacuum plugs that can damage the supply lines..

The device and principle of operation of the oil pump of a chainsaw

For lubrication of the working tool of a gasoline saw, a forced supply of fluid from the supply tank is used. The principle of operation of the oil pump of a chainsaw is based on the translational movement of the plunger, which pumps the substance into the lubricating channel..

Device and principle of operation

The oil pump is installed on the side surface of the engine crankcase closer to the chain tool drive gear. The pump is a plastic or metal case, inside which there is a cylinder with a plunger.

The pump is attached to the engine crankcase with several screws and has a hole for installing the drive shaft. There are designs with separate protective covers.

Rotation is transmitted from the chain pinion or directly from the nose of the engine crankshaft. If sprocket transmission is used, the pump only runs while the chain is moving. At idle speed, oil is not supplied to the rubbing surfaces. If the pump drive is installed on the crankshaft, then the lubricant is supplied continuously, regardless of the speed..

When the engine is running, part of the torque is transmitted to the plunger, which is a steel rod. The part of the part installed inside the cylinder has a milled flat. There are 2 holes on the cylinder body that serve to take oil from the tank and then pump it into the channel. There is also a chamfered groove on the plunger body that contacts a fixed pin on the crankcase. Due to the interaction of the nodes, the translational movement of the plunger is ensured.

The plunger device includes a drive gear made of metal or plastic. In the design of the drive, one of the gears is made of a soft material. When the unit is jammed, the teeth are cut off, protecting the other element from damage.

When the part rotates, the holes on the cylinder wall alternately overlap. This causes pressure fluctuations. By reducing the pressure, a portion of the oil is taken into the cylinder cavity, which is then pushed out into the lubrication line. Since the crankshaft rotational speed is 5-12 thousand rpm, the pulsations of the lubricant flow are smoothed out, the supply becomes continuous.

In professional saws, a variable-flow pump is used, which features the shape of the drive gear teeth and an additional hold-down spring. The design allows you to change the amount of stroke of the plunger in the cylinder.

Affordable DIY solutions

Fun Pencil

How to adjust

The change in the parameters of the pump is made by adjusting the plunger stroke. For this, a special screw is used that turns the eccentric, which limits the mobility of the rod. On the saw body there are arrows and inscriptions Min and Max, explaining the principle of operation of the element.

How to eliminate oil leakage in a chainsaw / Chinese chainsaw 4500. Oil pump repair

The video examines the repair of a chainsaw oil pump and its sealing in the case. And this is a similar video.

Insufficient flow of the fuel mixture from the carburetor into the cylinder or a violation of the correct ratio between fuel and air mixed in the carburetor can occur for several reasons: due to clogging of the air filter, unregulated carburetor, clogging of its channels or filter mesh.

As a rule, the repair of chainsaws is not complete without cleaning the air filter, since it gets dirty quite quickly. When this happens, the flow of air into the carburetor is reduced, the fuel mixture at the exit from it is too rich, which disrupts the normal operation of the engine. How to remove the clutch of a chainsaw how to remove the clutch on a benzo saw how to remove grip on benzo pila Replacing an asterisk on a Chinese chainsaw Replacing a chain saw’s leading sprocket on the clutch is very useful. Remove the dirty filter for cleaning carefully so that dirt from it does not get into the carburetor. The filter should be cleaned or washed in water with some kind of detergent, dried and reinstalled.

The misalignment of the carburetor is eliminated by adjusting it. This is usually done with three screws. maximum and minimum speed and idle screw. Adjustment must be carried out in strict accordance with the instructions, non-observance of which may lead to engine damage.. Some saw manufacturers keep only one adjustment screw (idle speed). in order to exclude unwanted interference by inexperienced users with the operation of the carburetor. For an example of adjusting the carburetor of a chainsaw, see the article Working with a chainsaw.

If adjusting the carburetor does not help, you need to clean its channels and filter mesh, and at the same time check the integrity of the membrane. Carburetor. one of the most complex chainsaw devices, so you need to start disassembling and cleaning it with a full understanding of the responsibility of this operation. It consists of many small parts, which have the peculiarity of jumping out of their places imperceptibly and being irretrievably lost, so that, having disassembled this capricious device, you can not assemble it..

Below is a diagram of another chainsaw carburetor.

If there is no experience and self-confidence, it is better to entrust the repair of the chainsaw carburetor to a specialist of the service center. Sometimes for high-quality cleaning of the carburetor it is necessary to use ultrasonic cleaning..

Muffler. Often, the cause of engine malfunction, especially in the case when the engine normally operates at low speeds and stalls under load, is clogging of the exhaust gas spark arrester with combustion products, which prevents normal exhaust. Repair in this case consists in removing the muffler, disassembling (if it is collapsible) and wet cleaning it from carbon deposits using detergents. A non-dismountable muffler is dried with a hairdryer after washing. Remember that carbon deposits contain substances that are carcinogenic, and dry cleaning, due to which they can be inhaled, is not acceptable.. When removing the muffler, plug the engine outlet with a clean cloth..

Open circuit

This is mainly due to overheating during operation. Overheating is caused by a lack of lubricant supply or clogging of the oil passages with dirt. First of all, all oil channels are cleaned, the inside of the chainsaw is cleaned of debris (sawdust) in the area of ​​the drive sprocket and the tire groove. Only then can a new chain be installed. If a problem is found in the operation of the oil pump, the saw must be repaired in a specialized workshop..

The engine does not develop power (stalls under load)

One more reason is added to the previously listed reasons – it is required to adjust the carburetor or clean the muffler. The adjustment is carried out with the adjusting screws. Detailed information on this issue can be found on the pages of the site. The video shows the process of detecting and repairing a chainsaw failure.

Engine won’t start

In this case, it is necessary to check the gap between the spark plug electrodes. It should be 0.5 mm. At the same time, the electrodes must be cleaned of carbon deposits. In most cases, this is sufficient to get the engine running again. To the same extent, starting is affected by contamination of the carburetor, fuel and air filters. After washing them, the engine, as a rule, ceases to be “capricious”. On the pages of the site and the Internet there are many photos and videos on restoring engine performance.

Major malfunctions and their elimination

The main malfunctions that you can correct yourself and how to fix them are described in detail in the “Operating Instructions”.

Broken starter cord

Partner 350 is found quite often on chainsaws, and on all chainsaws, therefore Partner 350 is no exception. This malfunction is not difficult to rectify yourself. After watching the video, it becomes clear how a broken starter cord is replaced.

User’s manual

The manual contains recommendations, following which the owner of the Partner 350 chainsaw will not encounter problems when handling it. The safety measures and rules for operating the product during operation are described in detail. The issues of repair, maintenance and care of the Partner 350 chainsaw are highlighted.

The types of chainsaw repairs allowed to do it yourself are determined by the instruction manual. All other faults are rectified in a specialized workshop..

Partner 350 manual

The operating instructions should always be at hand, especially if this is your first chainsaw and you just bought it. Be sure to read it first, and use it whenever questions arise while handling the instrument. You can download and print the instruction manual for the Partner 350 chainsaw using the link below..

The best chainsaw for a summer resident – Partner 350

The Partner 350 chainsaw is a relative of the famous Husqvarna brand, as Partner is a subsidiary of Husqvarna. Lightweight and convenient, reliable and simple, Partner 350 has found wide application in summer cottages and in private households. Pruning branches, branches, felling trees – this is not a complete list of works that can be done with a saw easily and naturally. A quick overview will help you get to know this in more detail..

Chainsaw Partner 350

• Specifications
• Device
• Preparing the saw for use
• Pros and cons of the Partner 350 chainsaw
• Major malfunctions and their elimination
• Engine won’t start
• The engine does not develop power (stalls under load)
• Broken starter cord
• Open circuit
• User’s manual
• Testimonials

Specifications

According to its data, Partner 350 belongs to the household (amateur) type and fully satisfies the needs of any consumer. For a general acquaintance with the chainsaw, just look at its main characteristics.

Partner 350 specifications

For those familiar with chainsaws, one glance is enough to determine the nature of the 350 Partner. A sufficiently powerful engine and a decent length of the tire indicate that it will be an indispensable assistant on the farm, but it is hardly suitable for professional felling.

Chain lubrication system

In case of significant (small is considered normal) oil leakage, it is necessary to check the tightness of the connection of the pipes to the pump unions. They can subside or crack. Violation of the tightness of the oil line, except for drips, can lead to insufficient lubrication of the chain. The pump begins to suck in air, which affects its performance. The violation of the tightness is eliminated by replacing the tubes or sealing them with a sealant.

The most serious failure of the lubrication system is cracks in the oil pump housing. In this case, it will have to be replaced..

DIY chainsaw repair

All chainsaw malfunctions can be divided into two main groups: engine malfunctions with all its components and systems (ignition, fuel supply system, cylinder-piston group, exhaust system) and malfunctions of other units (chain brake, lubrication system, clutch, tire, etc. .).

Engine malfunctions

• The engine will not start;
• starts up, but stalls;
• works unstable;
• does not develop power, i.e. works normally at idle, but stalls under load.

When repairing a chainsaw with your own hands, you need to act by elimination. check one by one all the possible causes of the malfunction, starting with those, checking and eliminating which takes less time (about the design and operation of a two-stroke engine, see here).

Ignition system. Almost all types of engine problems listed above can be caused by faults in the ignition system. Therefore, when they occur, it makes sense to start troubleshooting with a candle. This is all the more justified since the state of the latter can provide useful information about the operation of the fuel system. So, if a problem occurs, you need to unscrew the candle and inspect it..

The wire is disconnected and the candle is unscrewed with a special key.

If the plug is dry, this means that the problem is most likely not in the ignition system, but in the fuel mixture entering the cylinder. You can wrap the spark plug back and start the fuel system. If the spark plug is heavily splashed with a fuel mixture, then there is an excess of it. This can occur from a misalignment of the carburetor or a violation of the starting rules. The candle is wiped and dried, the cylinder is drained by shutting off the fuel supply and working with the starter. to vent the combustion chamber and remove excess fuel. Then put the candle in place and repeat the start.

The presence of a large amount of black carbon also indicates a malfunction in the fuel system..

The ratio between oil and gasoline in the mixture may be disturbed, the carburetor is not adjusted or poor-quality oil is used. The candle is washed in gasoline, cleaned with a needle or an awl from carbon deposits, the electrodes are cleaned with a fine sandpaper and installed in place.

In all these cases, it will not be superfluous to check the gap between the spark plug electrodes. Depending on its brand, it should be in the range of 0.5-0.65 mm. It is also necessary to check the spark plug gasket. If it is worn out or damaged, the tightness of the combustion chamber may not be ensured, which leads to a decrease in compression in the cylinder and problems in engine operation..

Even if, when checking the spark plug, there is good reason to believe that the problem is in the fuel system, you need to check the spark plug for the presence of a spark. If only to be sure that everything is in order with this. For this:

• put the ignition cable on the spark plug;
• using pliers with insulated handles, apply the thread or nut of the candle to the cylinder;
• pull the starter handle and watch. is there a spark or not.

If there is no spark, you just need to replace the spark plug. If the new spark plug does not have a spark either, you need to check the condition of the high-voltage wire for an open circuit and contact with the spark plug..

The reason for the absence of a spark may also lie in a faulty ignition module or a violation of the gap between it and the flywheel magnetic circuit. It should be 0.2 mm. A gap violation becomes especially likely if the saw was disassembled before the flywheel and ignition module were removed. The gap is set with a 0.2 mm spacer placed between the flywheel boss and the ignition module. Defective ignition module must be replaced.

Having checked the ignition system in this way and not finding a malfunction, you can go to the fuel mixture supply system.

Fuel supply system. If by inspection of the spark plug it was found that fuel does not enter the cylinder, all possible reasons for this need to be considered. This could be:

• no fuel flow from the tank due to a clogged hole in its lid (breather), while a vacuum is created in the tank, which prevents fuel from flowing out;
• contamination of the fuel filter installed in the tank;
• non-flow or insufficient flow of the fuel mixture from the carburetor to the cylinder.

Husqvarna 350 chainsaw oil pump modification for increased flow

To diagnose the first two reasons, it is enough to disconnect the fuel hose from the carburetor and see if fuel is leaking from it or not. If it flows with a full stream, the breather and filter can be left unchecked, if it does not flow or flows weakly, we can assume that the cause of the malfunction has been found. The breather is cleaned with a needle. The fuel filter is removed through the filler opening of the empty fuel tank, with a wire hook, together with a suction hose from which the filter is disconnected and cleaned or replaced with a new one. Chainsaw manufacturers recommend changing the fuel filter every 3 months..

Insufficient flow of the fuel mixture from the carburetor into the cylinder or a violation of the correct ratio between fuel and air mixed in the carburetor can occur for several reasons: due to clogging of the air filter, unregulated carburetor, clogging of its channels or filter mesh.

As a rule, the repair of chainsaws is not complete without cleaning the air filter, since it gets dirty quite quickly. When this happens, the flow of air into the carburetor is reduced, the fuel mixture at the exit from it is too rich, which disrupts the normal operation of the engine. Remove the dirty filter for cleaning carefully so that dirt from it does not get into the carburetor. The filter should be cleaned or washed in water with some kind of detergent, dried and reinstalled.

The misalignment of the carburetor is eliminated by adjusting it. This is usually done with three screws. maximum and minimum speed and idle screw. The adjustment must be carried out in strict accordance with the instructions, non-observance of which may lead to engine damage. Some saw manufacturers keep only one adjustment screw (idle speed). in order to exclude unwanted interference by inexperienced users with the operation of the carburetor. For an example of adjusting the carburetor of a chainsaw, see the article Working with a chainsaw.

If adjusting the carburetor does not help, you need to clean its channels and filter mesh, and at the same time check the integrity of the membrane. Carburetor. one of the most complex chainsaw devices, so you need to start disassembling and cleaning it with a full understanding of the responsibility of this operation. It consists of many small parts, which have the peculiarity of jumping out of their places imperceptibly and being irretrievably lost, so that, having disassembled this capricious device, you can not assemble it..

Below is a diagram of another chainsaw carburetor.

If there is no experience and self-confidence, it is better to entrust the repair of the chainsaw carburetor to a specialist of the service center. Sometimes for high-quality cleaning of the carburetor it is necessary to use ultrasonic cleaning..

Muffler. Often, the cause of engine malfunction, especially in the case when the engine normally operates at low speeds and stalls under load, is clogging of the exhaust gas spark arrester with combustion products, which prevents normal exhaust. Repair in this case consists in removing the muffler, disassembling (if it is collapsible) and wet cleaning it from carbon deposits using detergents. The non-dismountable muffler is dried with a hairdryer after washing. Remember that carbon deposits contain substances that are carcinogenic and should not be dry cleaned, which could result in inhalation. When removing the muffler, plug the engine outlet with a clean cloth..

Some of the reasons a muffler can clog. this is the use of a fuel mixture with an excessive amount of oil (the amount of oil is more than the manufacturer recommends), and the use of either oil not intended for two-stroke engines or low-quality oil.

Replacing the oil pump on the Partner 351. The pump does not fill the chain with oil.

Cylinder-piston group. Malfunctions of the cylinder-piston group are among the most serious. This is the worn out cylinder and piston, scratches and scuffs on their surfaces, wear or sinking in the grooves of the piston rings, wear on the crankshaft bearings. Most of these malfunctions lead to a drop in cylinder pressure and, as a result, to the inability to start the engine, or its inability to deliver full power. There are several ways to assess the state of the cylinder-piston group (CPG).

You can remove the muffler and look through the opened window, in which part of the side surface of the cylinder is visible. Despite the limited review, a general idea of ​​the state of the CPG in this way can still be obtained.

It is useful to measure the compression in the engine, which is informative enough regarding the condition of the parts of the CPG. The operation is carried out using a compressometer installed in the candle hole.

The crankshaft is turned using an electric motor (drill) with a flexible shaft or manually with a starter, while controlling the pressure on a pressure gauge. The latter for a working chainsaw should be at least 8-9 atm (0.8-0.9 MPa). With its decrease, the engine power also decreases. At a pressure of 5 atm, the engine may work, but only at idle.

It is possible to accurately assess the state of the CPG only by completely disassembling the engine. by disconnecting the crankcase from the cylinder and removing the piston. If the latter has seizures, chips or deep scratches, it must be replaced. With regard to the cylinder, if the surface is worn out or damaged, it is possible to bore it to the repair size. The reason for low compression may be wear or coking of the piston ring. A serviceable ring should be clean from carbon deposits, sit freely in the piston groove and press tightly against the inner surface of the cylinder.

Chain brake

Replacement of wearing parts

If you do not replace wearing parts in time, their excessive wear will adversely affect the rest of the chainsaw. In particular, if the tire and drive sprocket are not changed in time, the increased vibration will adversely affect the crankshaft bearings. The maximum depth of the sprocket teeth must be 0.5 mm. In practice, sprockets are often operated to a wear depth of 1 mm or more. unaware that this leads to an increased load on the crankshaft bearings and their accelerated failure. When 3-4 chains are worn, it is necessary to change the tire itself, by which time its wear reaches its limit values.

Chainsaw bar wears especially in the area that is cut most often, usually. this is the underside of the guide bar. For even wear, with each chain change, the bar must be turned 180 ° relative to the horizontal axis..

When installing a new chain, install a new drive sprocket. Since the life of the drive sprocket is twice the life of the chain under normal load, it is advisable to use one sprocket for alternating operation of the two chains. This allows the sprocket and chains to wear out almost at the same time. If a new chain is placed on a worn sprocket, the drive links of the chain wear out much faster. To operate your chainsaw economically, always use together: one guide bar, two chain sprockets, four saw chains.