Air leaks and crank seals.

[Whiskers]

Maybe it's unnecessary, but I often smear a light coat of sealer on the outside of the crank seals and gaskets I don't want to worry about.

 

[Boomer 87]

Well tore the saw down it was really in good shape,put the jug on the flatstone with some 400grit in a figure 8 to make sure it was flat, did the same with the intake manifold (it was actually warped some). New base gasket, intake gasket, crank seals, carb flange gasket. Also the intake manifold has a nasty casting line inside and real sharp edges, so i did some blending and smoothing inside. Reassembled, test run. had to retune but I think its good, gonna set the max rpm about 10-10.5k and run it.

 

[Boomer 87]

Im crossin my fingers

 

[Lone Wolf]

I'm not familiar with the saw either .However as a general rule if the saw acts differently when tilted it normally would be a fuel line leak, torn boot or something like that .If it progressively appears to lean out with run time it most likely is a seal going bad .Usually it's the clutch side seal .

I know for example for years people blamed a faulty carb on Stihl 200t model but most times it was a bad seal caused by a worn crankshaft bearing .I'd imagine Stihl sold a million dollars worth of Zama C1Q carbs at 90 bucks a pop which didn't solve the problem .

I might add with all that said that to trouble shoot a saw over the internet is at best a guessing game .All ideas might have some merit though based on passed experiances .

Dont worry they will need the carb at some point!

 

[Boomer 87]

Update on the 375. I went out and did some tuning just a bit ago. Got it warm set the idle and low speed. Did some test cuts with a fresh sharpened chain. The only thing i did to gain any umph out of it was blended the intake manifold and advanced the timing. I put the tach on it and i was still getting light four stroking at 13k!!!! So i backed it down to about 11,500. Its four stroking heavy did some more test cuts it maintains 8-9k in the cut with me pushing it alittle. So im impressed. I may have to throw a spare 24" bar on it.

I think i could push it to 12-12.5k but idk if i should it runs pretty good where its at