034 better cooling flywheel

[Clarkc9743]

Hello all I have come to notice that my 034 hybrid seems to be having heat soaking and cooling issues when running in longer cuts and it's hot out. Because I'm 98% sure it is boiling the fuel if I shut it off and it sits it will run like crap for a few seconds or will sometimes idle funky for a second or 2 between cuts. I have vacuum and pressure tested with 0 issues along with a oem carb and a china. I was wondering if there is a difference in how well certain flywheels cool vs others. I know the 024 and 026 have differences and I noticed there are several different versions of the Stihl flywheels where the cooling fins appear more curved than what I have. Just curious if anyone knew about this subject or not. But I believe I have a early 034 flywheel. Because it is shaped like this and doesn't seem to have very large cooling fins on it. Now it may just be something I'm stuck with for shoving a a 70cc saw into 56cc cases. Or it may be the low rakered hex filed 325 9 pin sprocket chain combo too.

 

[Bigmac]

I would highly doubt it’s boiling the fuel, there is a big gap between the fuel system and heat, and a small amount of extra cooling is probably not going to effect the fuel being separated case and intake. I have an 036 pro and an 034 super that act up and both pass pressure vac tests. I think they both need seals or something. But they don’t “leak” I think it’s common for this chassis

 

[Clarkc9743]

That makes me feel a big better. It only does it when it's shut off after being super hot or after consecutive long cuts. It may be hard to believe but my what gave me the idea was my 462. If I cut off a large stump when it's 100 and then let it sit it won't restart without some effort. I listened close and heard the gurgling of fuel boil .

 

[Michael Rupley]

Richen up the high speed a little and increase the oil in the mix.

 

[drf256]

It’s pretty normal for a saw to run differently when it gets hot and is buried in long cuts, especially ported saws with increased compression.

In the summer, you have to tune for the way it’s gonna run when it’s loaded. Like Mike said above, fatten it up.

You’re probably getting vapor lock in the carb from the heat when it sits. You can also try a different fuel mix.

My ported 3120 won’t start at all after long milling cuts when it’s hot out. I have to let it sit for 10-15 minutes. And there is nothing wrong with the saw.

 

[Clarkc9743]

I discovered a large part of the issue. The gasket on the decomp was leaking. It has gotten rid of the weird stumbling and appears to run cooler now. Along with that I actually put a time light on it when I changed the flywheel and it was at 34*. I set the other at I think 29-30. It hasn't been hot enough to see about the restart issues. But I'm fine with that because I feel nearly all saws will do it at some point. Seems to be all good now.