Problem running saw ???

[TimberCutterDartmoor]

My trusty (until now) Stihl 036 (in fantastic nick, masses of compression, no other probs) is running lean intermittently i.e. some days it runs normally, others it revs its knackers off and dies after the over-run and is more awkward to re-start. Or this might happen on and off in a single day.

 

Plug colour is bang on, light brown. Carb serviced only in the spring.

 

Don't want to blow it up!

 

 

Have checked usuals i.e. manifold and can only assume an air leak elsewhere in the crankcase?

[paddy]

you cant blow a 036 up , had 2 they were bad to start when they got older not bad wee saws tho

[Tyz05]

Changed crank seals on my old 039 while ago. No leak on pressure check but leaked on vacuum test. Was suffering from similar symptoms.

[TimberCutterDartmoor]

Changed crank seals on my old 039 while ago. No leak on pressure check but leaked on vacuum test. Was suffering from similar symptoms.

 

Do you mean the main one in the middle between the split or the two outer ones by the crank bearings?

[burrell_]

it could be a oil seal on the crank that lets the air in

[Robert Raven]

Had similar intermittent symptoms on an ms390, turned out to be a pinprick hole in the fuel line, £3.50 to fix!

[spudulike]

The more common seal to go is the one on the clutch side but would personally get the engine pressure and vac tested before it really goes - seizure is a possibillity if a seal is leaking - turning the H screw out 1/4 turn will help it not happen but the checks will sort you out.

If you get stuck PM me!

[Tyz05]

Think it was clutch side but changed both. Not much to do,can be done without splitting cases. That section of fuel pipe as previously mentioned is worth checking out.