stihl 066 redeye wont idle

[ozarkjeep]

I had just a few minutes last night to fiddle with this new to me saw.

removed muffler, piston and jug are shiny clean, look to be in great shape.

saw starts easily, and will rev with some feathering of the throttle.

doesnt want to idle though.

Ive been searching and reading here.

possibly a leaky crank seal, or Id guess the idle fuel circuit of the carb might be clogged up.

can I richen the low speed jet to say.. 3 turns out and see if that makes a difference?

trying to diagnose without a leakdown test.

any other things that might make a saw not want to idle?

 

[blsnelling]

If it has to be turned out 3 turn you still have a very real problem. Take the carb off and go through it entirely. It's simple to do. Check your impulse and fuel lines while you're at it.

 

[Kingsley]

+1:agree2:

 

[Rookie1]

Does he mean three whole turns or three flats of the screwdriver,I guess thats what I mean, meaning 1 1/2 turns. But if it revs up with feathering the throttle ill bet carb needs attention.

 

[ozarkjeep]

I removed carb

cleaned it very well.

both fuel circuits are free and clear.

it will run, and idle with 1.5-2 turns out on the low screw. ( full turns Rookie1)

but its idling faster than I would like, even with the LA screw all of the way in.

so at this point, I am reasonably sure its got an air leak.
carb to manifold boot looks good.

what else do I check before looking at the flywheel side crank seal?

ive searched and read and lakeside generally says on these saws the seals are good until the crank bearings go bad.

there is not really any play in the flywheel.

How else would I check the crankbearings?

 

[Rookie1]

Im not a pro but I would partially disassemble saw and vacuum/pressure test engine. i use old innertube to cover ex.port and intake. I have a mightyvac pump I use for bleeding brakes. Not sure what to do if you dont have one.

 

[stihl86]

I removed carb

cleaned it very well.

both fuel circuits are free and clear.

it will run, and idle with 1.5-2 turns out on the low screw. ( full turns Rookie1)

but its idling faster than I would like, even with the LA screw all of the way in.

so at this point, I am reasonably sure its got an air leak.
carb to manifold boot looks good.

what else do I check before looking at the flywheel side crank seal?

ive searched and read and lakeside generally says on these saws the seals are good until the crank bearings go bad.

there is not really any play in the flywheel.

How else would I check the crankbearings?

Are you sure the manifold is OK ? It's next to impossible to tell by looking at it. I just worked on a MS460 that would not idle down below 3200. Ran fine WOT. Vac/Press test revealed a small crack in the manifold. Never would have found it short of removal.

 

[bigbadbob]

but its idling faster than I would like, even with the LA screw all of the way in.

I think the LA should be turned out for a slower idle???

 

[ozarkjeep]

I meant to say the LA screw was turned OUT.

mis spoken.

if I leakdown test it, I block off the exhaust, and the carb?

 

[ozarkjeep]

Ill remove and check the carb boot too.

If I can figure out how to get it off...
this old 066 is different from my other saws with this metal housing in front of the carb, and the plastic house behind the carb, that almost seems to be glued to the fuel tank?

I need a service manual, and IPL for this saw.

 

[stihl86]

What other saws you have? Can you switch carbs for test and see if problem remains? You really should do a vac/press test (or have it done). A competent Stihl dealer can do it on that saw in 15 min. I know. I do it every day. It's going to take 30-40 mins to inspect manifold. That saw comes apart the same as all Stihl pro saws (excluding020T family)

 

[ozarkjeep]

the other saws I have are considerably smaller, not sure any of the carbs would work.

024,029S,ms310,034,036

Ill remove the boot and hope to find a crack in it.
otherwise, its $$$ for crank bearings and seals I guess.

 

[ozarkjeep]

well, I decided to look into the saw tonight.

I found ONE cylinder base bolt that was unlike the others.

and then found that it was LOOSE, and when tightened it continued to spin.

here is a pic.

I guess I need to remove the cylinder, retap the hole in the case ( to a larger size) replace base gasket and try again?

have NOT pressure tested the engine yet.

would a leaky base gasket cause a NON-idle issue?

 

[Rookie1]

Im not sure about that but my moms homelite leaf blower had all its bolts loose and would run funny. I would adjusat carb run good for a while then funny again. I suppose it could.

 

[blsnelling]

You almost positively have a significant air leak if the L screw is that far out and the idle still can't be turned down. Check your intake boot and then look to the crank seal.

 

[ozarkjeep]

So.

Bsnelling,

you dont think this loose cylinder base bolt could cause the air leak thats making it hard to tune?

I removed the intake boot, it appears to be solid.

pulse hose had a small place where the reinforcing cords show, but only when its stretched out way further than necessary.

 

[blsnelling]

My appologies. I missed that part. Yeah, that could easily let the base of the cylinder leak and cause your idle problems. Check into getting a Timesert put in there. That's a critical fastener.

 

[ozarkjeep]

gotcha.

thanks for the clarification!

 

[ozarkjeep]

Upon further tear down...

the flywheel was already loose, and the seal behind the flywheel is visibly torn up.

My guess is now the saw needs crank bearings, and crank seals.

anyone got a good 660 bottom end for sale?

I might be better off parting this one out.

:censored:

 

[ozarkjeep]

what is this old saw worth, if running well?

I see cheapstihlparts has a crankcase for $110 on eghey.

that would put me at $310 in the saw.

thats big money for this saw in my opinion...
am I wrong?