Saw air leaks

[L34]

Hi all at AS.If a saw had a vac leak (not that any of mine have) would one of the first checks be to screw the idle screw right out.If the saw doesnt stop or keep high revs this could be a vac leak right?
I know other problems can cause this but just applying this to vac leaks.
Cheers,Chris.

 

[a. palmer jr.]

Usually the first thing I do is check the H and L screws to make sure they're right then I look for maybe some loose engine bolts like the ones holding the carburetor on and the cylinder base bolts. Also, it depends on what kind of chainsaw it is because some saws don't have intake boots or pulse hoses.

 

[buzz sawyer]

Hi all at AS.If a saw had a vac leak (not that any of mine have) would one of the first checks be to screw the idle screw right out.If the saw doesnt stop or keep high revs this could be a vac leak right?
I know other problems can cause this but just applying this to vac leaks.
Cheers,Chris.

I understand your thinking on this but in order to draw fuel from the low side mixture needle, the air has to go down the throat of the carb . If it were leaking at the cylinder base, decomp valve, or impulse hose, it wouldn't draw fuel to keep the saw running. Someone tell me if I'm wrong.

 

[a. palmer jr.]

It depends on how big the leak is. If it's a crack it could still draw some fuel, just not enough. When you check a saw engine for air leaks you look everywhere.

 

[cus_deluxe]

I had the exact symptoms u described happen because whilst putting carb back on my 288, the gasket slipped off one of the screws. Still bolted down tight and still started but would run on and keep climbing rpms.

 

[Wood Doctor]

It depends on how big the leak is. If it's a crack it could still draw some fuel, just not enough. When you check a saw engine for air leaks you look everywhere.

Agreed. Worst air leak of them all is the crank seals. Doesn't happen very often but when it does, it's a nightmare. Then the whole engine has to be taken down. Many just part out the saw.

 

[L34]

Would rather rebuild a saw than part it out.My father was given an 066 for spares that the bloke said was no good.He got it started but very high idle.Checked saw and no seal behind oil pump.The saw would still pick up petrol but couldn't tune it. I split the saw,replaced gasket,bearings and seals.Saw now running good.If I wind the idle screw out saw will stop,so assume no vac leaks (didn't have it vac tested probably my bad).The top of the cylinder was only average but still had 150psi.Will see how it goes.This is why i asked the original question on winding the idle screw out.
Cheers,Chris.

 

[a. palmer jr.]

Was given an 015L because they thought I could use it for parts, in about an hour I had it running. Required a carb cleaning and points cleaning and a general washing. I don't parts them out unless there's not much left of them..

 

[L34]

Costs us a lot more to rebuild our saws in Australia than USA toem bearings $40ea,oem gasket set $70.But i still do this as it gives me something to do and keeps me learning.
Cheers,chris.

 

[a. palmer jr.]

It's fairly cheap to build most saws here but there's still a brand or two I shy away from..