Cleaning carb on smoking Stihl

[coppicer]

22 hours ago, spudulike said:

Just rattle it against the compression, no need to use a solid stop or clamp any part of the engine.

It wasn't keen to undo it on "low", but on the highest setting it came off and span up immediately. Thought there'd be more crud behind the clutch, but it's not that bad. I will give it a blast of air later. The crankshaft stub seems not to have any damage, and it has no play or slop. Worm spring likewise appears undamaged. Noticed the pinion of the oil pump. So that's how it fits together. Interesting.

 

Following your suggestion I held the clutch up to the light. I can see gaps between the coils of the springs, so presumably not yet requiring replacement? (EDIT I do have some springs and shoes on order.)

 

I should be receiving a carb kit later today, so I will carefully disassemble and take a look. That should be fun.

EDIT: carb kit didn't come. Hopefully tomorrow.

 

Edited July 21, 2020 by coppicer

[spudulike]

It looks OK, not much wear on the clutch shoe holes or the spring hooks. Always difficult to judge at a distance but looks OK to me.

If it has been very hot, the shoes tend to get blued over or black in some cases. It looks OK to me though!

[coppicer]

Thanks spud, shoes have some gunk on them, but it wipes off, and they look shiny underneath, not sure if that's good or bad. Gave it a going over with compressed air, most of the crap on the saw was blown back into my face, looks a lot better now (saw, not face).

 

 

 

[spudulike]

It normally scrubs off when the clutch catches the drum as you rev the engine so now you have cleaned the rest of the crap from around the area, it should go back to shiny steel.

It can be an indication that the clutch isn't wearing evenly on the drum (the dirty bits being the low parts) but clean it off and if it doesn't slip, wouldn't worry too much about it on a saw this small.

If you can feel undulations around the inside if the drum or see wear when a flat edge is put across the clutch shoe then you need to make a judgement but have only ever seen excessive wear on much bigger saws such as 395XP and 372XPs.

 

[coppicer]

The carb kit has arrived. Since I have the new parts, and the old ones have been there for 6-7 years, I thought I'd replace them.I took the lid off the carb to find this. Intact, but a bit messy.

 

I removed the diaphragm, but found that instead of coming away cleanly the gasket had stuck to the body of the carb, as seen below. Does anybody have advice on removing this? Carb cleaner maybe? I have some liquid for removing labels, but worried that it could attack rubber components. I also have some WD40 degreaser. I have had a go scraping it away with a pick and a small screwdriver, but that seems very likely to leave scratches on the mating surfaces. 

 

 

I haven't yet checked the needle.

 

 

[Ratman]

Gently nudge it away with a scraper, try not to score up the surface, then any remaining just scrat away with a very fine emery, nice and steady is the key, patience. Blow main of it off with brake cleaner then finish off with compressed air.

[coppicer]

44 minutes ago, Ratman said:

Gently nudge it away with a scraper, try not to score up the surface

Bugger, think I already have ?

[Ratman]

Bugger, think I already have [emoji51]

Using a release oil or a degreaser can sometimes help to soften the remains. If you have scratched it slightly i wouldnt worry, just go over it with a fine emery and neaten it up best you can, it shouldn’t harm it. (As long as you havent created niagara falls that is [emoji15])

[spudulike]

I use a decent quality sharp wood chisel, sounds brutal but if you get a nice angle on it, the residue will come straight off. Don't worry about a slight mark or two....it isn't rocket science, the gasket material will seal fine.

[coppicer]

No chisel, but I do have razor blades! Will give it a shot.