Broken clutch - STIHL FS 86 brush cutter

Stihl FS 86Today was the time to maintain the surroundings of my land. For that I preferred to use my FS 86 STIHL brushcutter ( year of production 1989 ) rather than the CB 38 edger.
One detail surprised me immediately after starting the engine is that the head was idling jerkily, with jerks that went up to the handlebars ... weird ... the machine however correctly performed its job, it took its turns well and the vibrations and other jerks disappeared with acceleration.

I am the only user of this machine for which I perform regular maintenance, and only with a wire head ( square section 2.4 mm ). It is true that I have already found myself stuck in particular in the fence, but from there to break the clutch!

At the end of the work I decided to take a closer look. Engine stopped, I began to manually turn my head in both directions to see what it was. In the normal direction of rotation, no real worries, the rotation seems free to me, but in the opposite direction, important points of blockage appear from time to time!

view of broken clutch ...Mandatory autopsy, dismantling of the machine. In the first place I believed in a possible problem with the idler gear at the end of the shaft because the jerks were much more noticeable near the head, but the reduction gear is intact and perfectly greased. Disassembly and extraction of the clutch ( well ... of what remains of it ... ) with a socket of 13 then recovery of the remaining pieces, trapped in the crankcase.
what's left of the clutch ...A breaking point clearly appears at the level of the tension spring hook. This clutch is not the original one, I already replaced it in 2013 because it is a bit "tired". This time it will not have had much time to wear out! However, I had bought this part from a French supplier STIHL and not in China. Perhaps a "straw" in the cast iron ... I was left with a dismantling and cleaning of the engine block as well as the casings, this in order to eliminate as much as possible the small debris of cast iron which did not have failed to diffuse in the interstices, then to check the good condition of the clutch housing ( 4126 160 2900 ) which I will not be able to replace, part exhausted.
I took the opportunity to complete the filling of grease in the angle transmission, I only need the new parts which will arrive these days, and it will be able to resume its service.
Here are some pictures of the two pieces making up one of the weights:
clutch002 (160x120px]clutch003 [160x120px]clutch004 [160x120px]clutch005 [160x120px]
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CB38: the hoses are leaking!

UP00020 reservoirOnce is not customary, when we take the machines out of the winter, we sometimes encounter problems.
This is what happened recently, I noticed a slight fuel leak that came from time to time from who knows where at the carburetor ...

In fact the hoses had become porous and were leaking at the level of the carburettors. Of course impossible to find these in the trade and even less on the net.

The engine of this machine looks like one of a Homelite type F2020 for which I was able to download the exploded views ( see my previous article ) with the references of the parts.
If the references of the hoses no longer pass even on the Homelite site, on the other hand we can still find the tank fully equipped, and that on a Parisian site.
Luck was with me that day, the new tank has exactly the same fixing points as the original one, and therefore adapts perfectly to the machine. It also has a deflector screen positioned just under the exhaust, which the old one did not have.
Those interested can note the reference for a possible order from ADEPEM :

To carry out this repair, you must first remove the rear flange which blocks the cylinder. This, making a fiber gasket, normally ensures its tightness.
I say normally because on mine it has already been destroyed for several years, and in 2007 I had replaced it with a silicone seal ( AUTOJOINT from Loctite ) which held up very well.
I therefore repeated this operation when reassembling the new tank, but this time with a blue seal from BARDAHL. The result is the same, difficult BARDAHL blue seal [160x284px]to apply correctly, but it works.

Good repair to you!

new UP00020 tank

new tank mounted UP00020

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Maintenance on Honda HRF 464 SE lawn mower

Honda HRF464 mower side viewWinter will not be long in coming and, from now on, we must take care of the wintering of our garden machines.
In this little tutorial, I explain the method I used to perform the engine oil change on a 1994 Honda model HRF464SE self-propelled mower, equipped with the Honda GXV120 engine engine..

For information, this is an air-cooled 120cm3 OHV single-cylinder single-cylinder petrol engine ( overhead valve engine ), developing a power of 2.9 kW or 4 hp. The starting is done using a hand starter, the ignition is electronic. The oil capacity is 0.60 liters. It works with SP95 gasoline, and has no blade brake or other safety. The only controls available are throttle control and traction control. The cutting height is adjusted using 2 levers, allowing separate adjustment of each pair of wheels, in 5 possible notches.
It is an excellent machine, robust and reliable, bought 4650Frs ( a little over 700 € ... ) in June 1994 at a Honda dealer.

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Before reading the following, please know that I can in no way be held responsible for any damage that your equipment may suffer during or / and after this type of intervention.

The problem on this machine is the accessibility of the oil drain plug, because it is arranged in such a way that on the one hand, it is impossible to unscrew it completely, and on the other hand the oil will spill over the frame during the flow. For this second point, there is little choice, apart from the total extraction engine ... Without going that far, I still loose about 2 centimeters 3 bolts ( socket Ø13) retaining the engine to the frame, so as to be able to lift it slightly, this then allowing the release of the drain plug ( Ø10 socket to be preferred to a wrench ) located at the foot of the gauge. The oil will thus flow along a channel apparently provided for this purpose ...To collect the used oil, simply place a container of about 35cm in diameter below the machine, and voila! For my part, I did not encounter any problem at this level, I actually used the pit of my garagein which I planned a sliding wooden tray, receiving my basins and other utensils for the emptying!
To gain access to these 3 fixing bolts, it is necessary to remove the cutting blade ( Ø14 socket ), as well as the blade holder, to which the transmission belt is also connected. It will be preferable to remove the cover plate from the belt ( accessible from above and located between the engine and the rear of the frame ), fixed using 2 cruciform screws. This will greatly help in handling the belt, and checking it ...
You can release the blade holder downwards by using a small hammer, and by tapping lightly in the transverse direction of the axis. This operation releases it, which is often affected by corrosion in this area ... Once removed, be sure to clean the splines of the shaft as well as those of the blade holder.
In the event of low ambient temperature, run the engine for a few minutes to warm up and thin the oil, the draining will be faster. During the flow, take the opportunity to disassemble the launcher, in order to better check the condition of the cord, but also of the locking lever( plastic ) and its return spring. Also disassemble the spark plug (original type NGK BPR5ES), and after cleaning, check the correct spacing of its electrode, which must be between 0.6-0.7mm( manufacturer's indication ).
Once the oil change is complete, fill it with Special 4 Stroke Motoculture oil..

Problem on the chassis :
It may happen that the handlebar mounting platescrack at the bolts. This has happened to me before, and in this case it is necessary to replace the defective parts.

Preparation for storage *:

  • If the engine has been running, wait for it to cool for at least half an hour before cleaning it. Clean all exterior surfaces, touch up paint as necessary, and cover areas that may be oxidized with a thin layer of oil.
  • When stored, fuel oxidizes and deteriorates. Old fuel can cause difficult starting and gum deposits that can clog the fuel system.
    To avoid problems due to fuel deterioration, drain the fuel tank and carburetor.
  • Position the assembly so that the motor is level. Tilting the engine can cause oil or fuel to leak.

Draining the fuel tank and carburetor *:
  • Disconnect the fuel line to the engine and drain the tank into a container approved for fuel. If the tank is equipped with a valve, turn the fuel valve to the OPEN or ON position to allow draining.
    When the drain is complete, reconnect the fuel line and turn the valve to the OFF position .
  • Loosen the carburetor drain screw and drain the carburetor into a container approved for fuel. When the drain is complete, tighten the carburetor drain screw.
* Partial information from the European HONDA site
To help you in finding spare parts, here are some useful files to download in PDF format:
  • GXV120 HONDA Engine Owner's Manual
  • HONDA GXV120 Engine Maintenance Chart
  • GXV120 HONDA Engine Manufacturer Specifications
  • GXV120 HONDA engine diagram

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To order spare parts, here is the address of a website from which I have already purchased: http://www.jardimat-motoculture.com

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CB38 petrol trimmer

In this article, I will describe the repair I performed on my edger following a major oil leak.
I bought this device from Bricomarché in April 1995 for I believe 800Frs ( a little over 120 € ... ), and the address on the back of the user manual states the USA. I first looked for any information on the net and, after spending some time behind my keyboard, it is clear that they are simply non-existent! At the same time, I wasn't expecting anything else, considering that my machine's brand hardly exists.
So if no supplier, no spare parts either.
Anxious to keep it in perfect working order because it is very practical to use, I set to work once again.

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Before reading the following, please know that I can in no way be held responsible for any damage that your equipment may suffer during or / and after this type of intervention.
top view of the machine front view of the machine rear view of the machine

This machine has a particularity: it does not have the 2 traditional handles that can be found on a brush cutter. For its handling, there is only an axial handle located just behind the launcher's cage, the throttle located below that can be manipulated with the index finger, and a handle in the form of an arch located a little more far on the driveshaft.

If you take a good look at the rear of the engine, you will be able to distinguish the traces of oils. On the right, is the exhaust, at the top center, the cylinder with the location of the spark plug (original type Champion RDJ7Y ), on the left the Walbro diaphragm carburetor ( this one being fitted with a manual fuel priming pump ... ), and at the bottom just above the fuel tank, the hatch which gives access after removing the 4 torx screw to the crankshaft.

Model identification :
Charlotte ... charlotte ... is this not the name of a potato? rolleyesLet's continue ... We can read one thing, The very important thing on this plate is its origin from the USA.
At a time when almost everything comes from China, it is rather reassuring !!!
It is therefore this plate that will have to be removed, in order to check the condition of the fiber gasket.
rear seal CB38 side [200x150] view of the nameplateFirst of all, I wanted to replace this seal with one of my own making, but the technical constraints of the material, its thickness and its shape soon made my good will! I ended up going with blue joint compoundview of a tube of joint paste, more practical to implement, and just as effective, since it is widely used in the automotive world! I still give you the dimensional drawing of the original seal, which was distorted in its thickness in places, deformations not visible on the photo.
I carried out this repair in November 2007, and today in April 2009, no more traces of oil, a clear sign that my new seal is holding up.

Engine oil :
But where can this oil come from, you will tell me? Well, if we consider that this engine is of the 2-stroke type, and that it uses a mixture of SP95 gasolinedosed at 4% of synthetic oil " Special Motoculture engine 2T", also taking into account that the tank has a capacity of 600ml, that gives us a quantity of oil of 24ml. A part of course is burned with gasoline, but there is enough left for the lubrication of the crankshaft.

Motor shaft
photo of the drive shaftWith the wire head removed from the machine, the drive axis then looks like the following photo:
On the other hand, the head is fixed using a plastic wheel ( no. 9 on this documentation) from which the bolt comes out very often, with the risk of losing it in the grass ... This is an American 5/16 "(7.94mm) diameter steel bolt( no screw on the right ... ) whose thread length measures 12 mm, with 8½ threads for an approximate diameter of 8 mm. The hexagonal head of the bolt corresponds to a Ø 13 mm wrench / socket. Note that this bolt has no marking, which makes it more difficult to examine.

If I refer to this conversion table and after having carefully measured it using my caliper, this bolt would therefore have the following characteristics:

Nominal diameter UNC Un ified Screw Thread - C oarse Series 
thumb mm TPI Pitch (mm)
5/16 " 7.94 18 1.41
tpi diagram
Hoping that this information will be useful to you in case you lose yours ... wink
Note :
This engine has never disappointed me, it still starts as well and as easily as when it started.
The disadvantage of this small machine: it does not have a clutch between the engine output and the transmission shaft. It therefore sometimes happens that the engine stalls during use, especially during the automatic unwinding of the line head (original equipment! )

Note :


I offer you for free download the multilingual user manual of this machine, as well as several links leading to an exploded view of the equivalent machine although more recent (a Homelite F2015, the cutting parts and various accessories are almost identical to those mounted on the CB38)

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You can order at this address:

This email address is being protected from spambots. You need JavaScript enabled to view it. 116 ROUTE DE THIONVILLE ZONE TILLY 57140 WOIPPY Tel: 03 87 30 16 17


[Edit of May 3, 2016] :

The link to the HOMELITE website ...

So I carried out new ( long ... ) research on the Internet, and I was still able to find a match ( perhaps partial, I did not check everything ... ) with a Homelite F2020 or UT-20788.

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It is understood that I could not be held responsible in any way for any error in the reference of a spare part.
This new link provides access to a PDF document concerning the F2020 model (UT-20788), and this is for informational purposes only.

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Maintenance on chainsaw YB701 Iseki Shindaiwa

view from left side of machine ...YB701 Iseki Shindaiwa chainsaw
(Japanese origin - manufactured in 1988)
For information, this is an air-cooled 47.9cm3 2-stroke single-cylinder petrol engine. The carburetor is a membrane Walbro. The capacity of the gasoline tank is 0.50 liters. The capacity of the chain oil tank is 0.25 liters. Lubrication is automatic by an adjustable flow pump. The length of the guide is 45cm. The machine weighs 5.2kg ( without guide or chain ). The starting is done using a hand starter, the ignition is electronic.

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Before reading the following, please know that I can in no way be held responsible for any damage that your equipment may suffer during or / and after this type of intervention.

It all depends on what you want to do on your machine but, for any intervention on the engine itself, you will have to remove the clutch as well as the flywheel.
Disassembling the clutch
For this you need to make an extractor, which you will attach to the flywheel in order to immobilize it. I offer you a listed photo of the tool that I thus produced:
view of the extractor to be made ...To make this tool, I used a mild steel bar with a section of 20mm and a thickness of 4mm, minimum length of 145mm. Measure and mark on your bar a first line 25mm from the edge, then the second at 16.5mm, the third again at 16.5mm, and finally the last 80mm further.
Draw a line down the center of the bar along its length. This gives you your drilling axes.
The first (the one 25mm from the edge ... ) will be drilled at 6mm, the second at 5mm and tapped at 6-100, the third at 6mm and the last at 4mm.
To use the tool, it is not necessary to remove the 2 locking levers ( not visible here ... ) of the launcher. It is just more convenient to insert the socket on the flywheel retaining nut.
Install the completed tool on the flywheel, then turn the machine over and clamp the tool in a vise. Using a pin punch ( 6-7mm minimum ... ), strike a small sharp blow transversely to the clutch ( see photo). Attention, this is an English step, that is to say that the tightening direction is the reverse of that of clockwise! Unscrew the part, and pay attention to the needle cage bearing, take the opportunity to check that it is still in good condition ... When you reassemble the clutch, also tighten it using the pin punch.


If your machine refuses to accelerate, suffocates and stalls, it is more than likely that there is an air intake in the gasoline inlet. First, and before touching the carburettor, check and clean with compressed air the vent nozzle, located at the front of the machine, in a round black rubber cap. Also check the suction pipe with its strainer . If the pipe is very soft and gets damaged under the fingers, it is imperative to replace it, it is the cause of your failure.

Engine oil :
But where can this oil come from, you will tell me? Well, if we consider that this engine is of the 2-stroke type, and that it uses a mixture of SP95 gasoline dosed at 4% of synthetic oil " Special Motoculture engine 2T", also taking into account that the tank has a capacity of 600ml, that gives us a quantity of oil of 24ml. A part of course is burned with gasoline, but there is enough left for the lubrication of the crankshaft.

Chain oil :
For this oil, please, no frying oil! only use oil intended for this purpose, the name " Chainsaw chain oil"being clearly indicated on the cans ( which can be found in 2L and 5L ) in all DIY stores.

search When I was looking for spare parts, I had a bit of trouble because the Yvan Béal group stopped selling this machine. However, I managed to find the address of a workshop that could provide me with it. If this is also your case, you must send your request by email preferably to the following address:

2 avenue Roger Salengro
93220 GAGNY
This email address is being protected from spambots. You need JavaScript enabled to view it.

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YB701 Iseki Shindaiwa Chainsaw Pictures

Following the request of certain owners of this chainsaw, and in view of the obvious lack of information about it, I have included in this article some photos taken during the intervention on my machine.
It goes without saying that to achieve them, its complete disassembly was necessary.
It is not inaccessible, but it requires a minimum of tools and attention.

punctuation iconBefore reading the following, please know that I can in no way be held responsible for any damage that your equipment may suffer during or / and after this type of intervention.

View after removing the handle and the housing :

view of the machine being dismantled ...

We can see on the right in blue the ignition coil, and in the background, the engine cylinder. In the center, the wheel with the fins ( which are used to cool the engine ), it is the magnetic flywheel, which delivers these impulses at each turn via small magnets, which are an integral part of an electronic hall effect ignition. . The transistor that receives these pulses is located just under the flywheel, attached to the lower part of the chassis. On the far left are the 2 fuel and chain oil tanks.

The fuel tank :

view of the fuel tank ...another view of the fuel tank ...On this tank, apart from the filler cap that I still left in place, we can clearly see the end of the fuel inlet pipe fitted with its strainer ( still in place in the tank ... ), and a little further to the left, a round hole which accommodates the vent nozzle ( round black rubber cap located on the top of the machine, at the front behind the safety handle, etc. )

The pipe with its strainer :

view of the fuel hose fitted with its strainer ...view of the deterioration of the fuel hose ...For information, the pipe is approximately 130mm long. The rubber material of which it is made becomes very soft over time, or even crumbles under the fingers. This obviously requires its replacement, under penalty of malfunction. The photo on the right shows the problem. This is the part that fits into the tank, and acts as a seal.

The magnetic flywheel :
view of the tool installed on the flywheel ...view of the tool installed on the flywheel ...

These 2 photos show the use of the tool I made to remove the flywheel. On the bar there is a hole left free, it is used to fix the tool to the frame by means of a large Ø4mm bolt.

The clutch :view of the oil pump gears ...

Once the tool is positioned on the flywheel, it is completely immobilized. Turn the machine 180 ° and clamp the tool in a vise. Remove the clutch using the method already explained on the previous page . The 2 visible gears are used to actuate the oil pump.
This done, we can now remove the steering wheel. Be careful, it is a keyed axis, and a small 'plop' will occur during detachment. A trained eye will have noticed the 2 marks on the field of the steering wheel: which I suppose to be notches made in the factory for balancing purposes.view of the magnetic flywheel removed ...

The carburetor :

multiple view of the carburetor ...internal view of the carburetor ...The carburetor that drives this engine is a Walbro membrane. Whatever problem you are having, don't touch the settings or open this delicate component! I did it on my machine, but I knew its engine was tight ... In addition, my carburetor problem was not one, the failure was due to the damaged fuel hose, which generated a significant air intake. I opened mine for you to show you precisely this famous membrane. The brass shutter in the center is called the butterfly, it is the throttle control. The 2 adjustment screws allow adjustment of the idle speed and the richness ( dosage of the air-fuel mixture ).

The oil pump :
view of the oil pump in place ...

Below the motor shaft is the oil pump, the flow of which is adjustable thanks to a small screw accessible on the top of the frame.
The exhaust :
view of the exhaust baffles ...Be careful when removing this very important part which serves as a load for the engine! I had the clumsiness of not paying too much attention to it, and I realized afterwards that it was possible to make a mistake during reassembly ( look closely at the photo, especially the baffles ... ). Not too bad in my case since the engine is definitely out of order, but on your machine, it is better to be careful!
Once the machine has got rid of all its little accessories that have become unnecessary for the moment eek, this is what the engine block looks like.
We can also distinguish the rubber connection serving as a flexible interface between the carburetor and the cylinder block.

view of the engine block ...

The engine :
view of the motor body ...

Come on, I'm happy, the last on the engine still assembled!

inside view of the cylinder ...inside view of the cylinder ...And now, drum roll ...
I'm going to show you the pictures of an engine that screwed up!

Here, it is true that we do not see much ... it is after that it becomes clearer ...

At the bottom of the image, we see the thread receiving the spark plug and, below, it is the light of the exhaust outlet. There are already emerging what I will call 'traces of fire' ...

On these other photos, at the foot of the exhaust light, we can see a trace ... more than a trace ... material has been removed !!!
inside view of the cylinder ...close-up view of the streaks ...

The piston :
view of the burnt piston ...

On this piston seen on the exhaust side, we can clearly see the ridges caused by the tightening.

Conclusion :

The consequences of all this mean that it would have been necessary to replace the piston ( equipped with the connecting rod, inseparable ) as well as the cylinder, no liner on this type of engine. We still manage to find second-hand engine blocks but I didn't want to venture ( that's the word! ) In an engine that was probably badly lived ... Suddenly, I scrapped my machine, and I bought from my usual dealer ( HONDA among others ...) a STIHL MS250 C-BE , equivalent model in terms of power and guide length. I admit I am not disappointed at all, it is an excellent machine, flexible and comfortable in use.

In spite of everything, I hope that these few pages will be useful to you, either to free you at first from what the dismantling of your machine can represent, whether in terms of technical knowledge or tools, or to directly repair it. and maintain it.

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