Possible air leak

[Ironworker]

I just put a saw back together and ran it, it idled and cut fine but after a couple of cuts it idled funny. It would idle fine then lean then fine then lean, rhythmatically every second or so. Would this be a symptom of an air leak?

 

[strtspdlx]

It may be. I'd try adjusting the low speed needle an hour or two richer. If that doesn't help time to test it.


Regards-Carlo

 

[Mastermind]

Maybe a small leak Numa. A massive leak makes one tough to even run. I'd check tune again, restarting at 1 turn out on both screws. That way you'll know if something is amiss. If you find that it needs to have the LS screw way out to idle, it might have a leak. I'd look at fuel lines, and impulse lines first.....if I thought it was wonky.

 

[Ironworker]

Just richened up the idle, that seemed to have solved it, is that a possibility, it was a brand new 365 that I just ported, probably factory settings.

 

[redfin]

Just had something similar yesterday with my 044. It would idle down and then come up to a high idle until I blipped throttle then repeat.

I swapped carbs and it's back to good again.

 

[sunfish]

I've had carbs act that way.

 

[Mastermind]

365 XT?

Change the coil to a 14,100 RPM limited coil from a 346xp. The coil on the XT advances the timing at a low RPM, and will make the engine surge.

 

[Ironworker]

I forgot to mention that it was stumbling off idle when I hit the throttle, but that also went away once I richened up the idle, hopefully that was it.