Chainsaw Repair

Hi folks,

I am having issues with fuel delivery (I think) while idling.  Saw starts and throttles well.  It will starve out while idling (leaning up) like it is running out of fuel and die.  If I catch it when it begins surging and throttle it, it will respond immediately, settle and return to idle.  I have removed, and rebuilt the fuel cap and venting doesn't seem to be an issue.  After it starves, it will start with a choke and do the same after 20 seconds or so.  I have revamped the entire fuel system, full kit (tried 2 new ones) and had the carb off/apart 1/2 dozen +.  I figured the low circuit might have been plugged.  Pulled the welch.  Spotless. New carb housing/intake block gaskets. 

I have set the L just rich enough to clear hesitation in the throttle.  I want to think it is perhaps simply needing richer L.  But, it will idle really well off of a cold start and suddenly and repeatedly starve out.  I have never experienced this before.   

I am stumped. 

Have you replaced the crank seals and/or done a vac/pres test?  Leaking crank seals can cause the saw to have a weak impulse signal at idle.   That'd cause the pump section of the carb to be weak....................which will allow it to lean out at idle as you describe. 

Seen that several times with Poulan Micros with old crank seals (that seemed to run fine otherwise).  That's a saw series with a 15 mile long fuel line that NEEDS a healthy carb pump section (and a healthy impulse signal).

 You didn't mention the fuel line, is it new.  Easy way to check the clutch side seal, take the clutch cover off and spray a little starting fluid around the seal with the engine running, if leaking that will slow down the engine.  Steve