Husqvarna Chainsaw: Must oscillate the choke to keep it running

[jeffbush]

Husqvarna 240 2 HP Chainsaw, 952802154 (16-Inch)

This chainsaw comes in three choke settings: Full, half and off.
Per instructions, I prime the bulb, set choke to full, crank twice, set to half, crank until starts (sometimes takes a few), let run a few seconds, then pull trigger, which sets choke to off.

THE PROBLEM: It only runs a few seconds, then shuts down. Especially if I pull full throttle. However I discovered a way to keep it running longer: I have to fiddle with the choke, oscillating it between the three choke settings about once every half second. If I leave it in any of the three settings too long, it shuts off. Only when I continue moving the choke lever in and out does it stay running.

 

[Bob Hedgecutter]

By having to manipulate choke to enable the engine to run tells us you are restricting air that is normally required for the engine to run properly at wide open throttle- thus we can assume the engine is sucking air from somewhere it should not be.
Loose engine pan- cracked fuel line- impulse- main crank seals- intake tract are all possibles.

 

[jeffbush]

@Bob Hedgecutter
Ok. BTW, when I'm manipulating the choke, that's actually with the throttle NOT pulled (basically just at idle throttle). Not sure if that was communicated properly. Does that make a difference?

 

[Bob Hedgecutter]

The choke restricts (chokes) the saws airway- so either too much air is in the system- or not enough fuel at idle.
So to compensate you have to choke some of the air out of the system to allow it to run.

Try turning the idle screw in a tad and see if it helps.
If not richen the L 1/8 to 1/4 turn (so you can return it to what it was if it changes nothing)