Stihl repairs and restoration thread

[JOEPRO]

It got it tore down. It's the main bearings are badly worn and causing issues. So yet another mis diagnosis! The original Stihl cylinder is like new. The piston could be re used but has one weird scratch on it. I'm almost certain someone jammed a screwdriver in there as nothing else could have caused it. I could sand it out but I think it's best get a new aftermarket piston for it.





Some additional clues for the crank bearing issue:




Anyway in terms of parts cost, this one will be a relatively cheap fix. They also installed brand new air filters and likely charged the guy for that and their mis diagnosis.

This saw is so clean it may end up staying in my collection I'll see.

 

[angellonewolf]

how do you clean them ?

 

[JOEPRO]

how do you clean them ?

I have a Lavor hot diesel washer that speeds things up alot. I use screwfix degeaser neat in a spray bottle and a stiff alloy wheel brush to scrub between hot washes. Then immediately blow it dry with compressed air.

Concrete saws can be slightly trickier and require some form of brick acid to get all the residue off. I did use some neat spirt of salts on this one to quickly remove the build up cement which worked very well but be warned its nasty stuff and wear appropriate PPE. I sometimes steep the parts in a weaker mortar residue remover instead.

 

[Kram]

Km111R now finished, ish.. I even cleaned it!
Adjusted valves, which were loose and may have never been adjusted before, it now starts with much less effort.

Theres two minor remaining issues. First is that pressing the primber bulb has a tiny air leak somewhere in the carb but does not appear to affect the running, its sucking fuel in ok.

Second is the choke return spring. It may have been broken, but the shaft had corrosion and was stiff, so I had to get it apart to clean up. Circlip came off fine. Spring has sprung, and is out of stock everywhere

Spring for Stihl FS89, FS89R, FS111, FS131 Brushcutters - 4180 122 3008

Spring Genuine Stihl Part OEM No. 4180 122 3008 Suitable for the Following Application's: KM 91 R, KM 111 R, KM 131, KM 131 R, BT 131, HT 102, HT 103, HT 132, HT 133, FS 89, FS 89 R, FS 91, FS 91 R, FS 111, FS 111 R, FS 111 RX, FS 131, FS 131 R

www.lsengineers.co.uk

Cleaned it up, oiled and reassembled without the spring. It just means the user needs to manually turn it back after starting. I'll get one ordered, just a pain to be waiting for it.

 

[Turbo]

Km111R now finished, ish.. I even cleaned it!
Adjusted valves, which were loose and may have never been adjusted before, it now starts with much less effort.
View attachment 479872

Theres two minor remaining issues. First is that pressing the primber bulb has a tiny air leak somewhere in the carb but does not appear to affect the running, its sucking fuel in ok.

Second is the choke return spring. It may have been broken, but the shaft had corrosion and was stiff, so I had to get it apart to clean up. Circlip came off fine. Spring has sprung, and is out of stock everywhere

Spring for Stihl FS89, FS89R, FS111, FS131 Brushcutters - 4180 122 3008

Spring Genuine Stihl Part OEM No. 4180 122 3008 Suitable for the Following Application's: KM 91 R, KM 111 R, KM 131, KM 131 R, BT 131, HT 102, HT 103, HT 132, HT 133, FS 89, FS 89 R, FS 91, FS 91 R, FS 111, FS 111 R, FS 111 RX, FS 131, FS 131 R

www.lsengineers.co.uk

Cleaned it up, oiled and reassembled without the spring. It just means the user needs to manually turn it back after starting. I'll get one ordered, just a pain to be waiting for it.

Valves? Is it 4 stroke?

 

[Kram]

Yes, "4 Mix" its called. It uses and burns 2T oil but has a timing gear, plastic cam, pushrods and rocker arms.

A bit different to Honda's 4T GX25-GX50 which uses clean petrol and has proper 4T engine oil and a wet timing belt.

Both are said to have better torque than 2T's.

 

[angellonewolf]

Yes, "4 Mix" its called. It uses and burns 2T oil but has a timing gear, plastic cam, pushrods and rocker arms.

A bit different to Honda's 4T GX25-GX50 which uses clean petrol and has proper 4T engine oil and a wet timing belt.

Both are said to have better torque than 2T's.

i had a 4 stroke honda last year i was supprised how good at cutting it was the 4 stroke seamed like the engine was not even running that fast but boy did it cut the grass

 

[Turbo]

i had a 4 stroke honda last year i was supprised how good at cutting it was the 4 stroke seamed like the engine was not even running that fast but boy did it cut the grass

A 4t should have more torque than a 2t and at lower revs.
It should be better than a 2t with a solid blade fitted but I would think a 2t would be better with a line head where the faster it goes the better it cuts.

 

[angellonewolf]

i was just supprised how slow it was reving but cut very well and yes you could hear it running but compaired to a 2 stroke what a differance

 

[Kram]

I'm unsure if any of these tools have gearing - chainsaws you can select a suitable toothed sprocket for the torque of the engine.
Hedge cutters have gears so that will be designed to suit the engine.
Trimmers are 1:1 at the clutch, along the pole and the angled head is usually a 1:1 bevel gear?
I am sure they could fit gearing somewhere or adjust the engine design to get torque and speed where it works best.

My engine auger has a 16:1 spur gearing on the output shaft, if I remember correctly. Its a 2t 52cc generic engine, so 12k rpm maximum? The output as I remember is only 100-200 rpm.

 

[JOEPRO]

A tip I can share and only recently figured out myself is that when buying main bearings for a Stihl or other small 2 stoke engine there are alot of aftermarket no brand options. And of course genuine parts.

Most of these parts, including the genuine one can come with no markings or COO. There can be significant cost saving by measuring the bearing and ordering an SKF or similar branded bearing from separate vendors on ebay etc. Like £3ish VS £16 each for TS410 bearings

SKF made in Italy, a bearing I know will be quality VS non brand aftermarket for several multiples of the price. Indeed the Stihl parts site will tell you the bearing dimensions so it's very easy to search for SKF separately.

2x TS410s are fixing to be completely rebuilt this weekend.

 

[Turbo]

Sometimes the cheaper bearings are not as good. For example the non genuine needle roller bearings for a peugeot back axle have a lot less rollers in them and wear the stub axles a lot quicker.

 

[JOEPRO]

Sometimes the cheaper bearings are not as good. For example the non genuine needle roller bearings for a peugeot back axle have a lot less rollers in them and wear the stub axles a lot quicker.

Yes it's not a good way to save money long term that's for sure!

There are only very limited number of bearings I'd use in cars. Such as INA or SKF being OEM suppliers. Or ideally genuine as most of the time the cost saving is not worth the hassle. With Mercedes I know the specific bearings that come for example in a INA box with the MB part number ground off at significant savings, so you know it's the same part! Or. Guibos etc.

As for the Stihl stuff, I'd say can't go wrong with SKF branded bearings made in Europe and avoid no name stuff

 

[Turbo]

There are people on ebay selling rebuild kits for pug back axles and they all contain lesser bearings!
As far as I know the genuine pug bearings are the only ones with the extra rollers. I guess they get them specially made.

 

[Kram]

Had a play with my chinese combi engine today. First I ran it for a couple minutes, tho the tester box says 15, anyway the result was

Around 150psi. Thats with the tester suggested earlier in the thread - has a valve at engine end to keep the hose presssurised.
Is that acceptable for a new engine? It has not done any work yet, only a brief test of the tools, running time of under 20 minutes, so it is far from being ran in. The bore looks new and clean.

The problem with this engine is hard to start - you need to pull it hard. Less than a hard pull will suck the cord back in and hurt your arm, which shows its igniting early and sending the piston back in reverse - wont be fun up a ladder!

I'm told a fix for this is to enlarge the coil to flywheel gap. I measure it at ~0.35mm with feelers. I tried adjusting and at 0.45mm theres no difference.

Its not easy to do! Currently Im putting a feeler in the gap but the thicker feelers have a bit too much spring in them. I'll try 0.8mm tomorrow, perhaps I can find some suitable plastic.

 

[dan.taylor.1]

Definitely worth measuring bearings to see if an skf version exists, often oem bearings are just a bagged skf one anyway! Make sure to get c3 ones though.

Also if anyone needs a workshop manual for stihl machines give me a shout, just acquired a load from an ex stihl tech with some special tools I bought.

 

[angellonewolf]

Had a play with my chinese combi engine today. First I ran it for a couple minutes, tho the tester box says 15, anyway the result was
View attachment 480153
Around 150psi. Thats with the tester suggested earlier in the thread - has a valve at engine end to keep the hose presssurised.
Is that acceptable for a new engine? It has not done any work yet, only a brief test of the tools, running time of under 20 minutes, so it is far from being ran in. The bore looks new and clean.

The problem with this engine is hard to start - you need to pull it hard. Less than a hard pull will suck the cord back in and hurt your arm, which shows its igniting early and sending the piston back in reverse - wont be fun up a ladder!

I'm told a fix for this is to enlarge the coil to flywheel gap. I measure it at ~0.35mm with feelers. I tried adjusting and at 0.45mm theres no difference.

Its not easy to do! Currently Im putting a feeler in the gap but the thicker feelers have a bit too much spring in them. I'll try 0.8mm tomorrow, perhaps I can find some suitable plastic.

i use a corn flake packet or those cards you recive when meeting people (cant remember what there called)

 

[Migmac]

i use a corn flake packet or those cards you recive when meeting people (cant remember what there called)

Business card

 

[Migmac]

Had a play with my chinese combi engine today. First I ran it for a couple minutes, tho the tester box says 15, anyway the result was
View attachment 480153
Around 150psi. Thats with the tester suggested earlier in the thread - has a valve at engine end to keep the hose presssurised.
Is that acceptable for a new engine? It has not done any work yet, only a brief test of the tools, running time of under 20 minutes, so it is far from being ran in. The bore looks new and clean.

The problem with this engine is hard to start - you need to pull it hard. Less than a hard pull will suck the cord back in and hurt your arm, which shows its igniting early and sending the piston back in reverse - wont be fun up a ladder!

I'm told a fix for this is to enlarge the coil to flywheel gap. I measure it at ~0.35mm with feelers. I tried adjusting and at 0.45mm theres no difference.

Its not easy to do! Currently Im putting a feeler in the gap but the thicker feelers have a bit too much spring in them. I'll try 0.8mm tomorrow, perhaps I can find some suitable plastic.

150 psi is good. Is there no decompression button on it ?

 

[angellonewolf]

Business card

yes