Tuning issue

[jerrycmorrow]

Just put a basket saw together, Olympyk 264. Good compression, rebuilt carb (soaked in solvent for three days), tillitson HS128B. Saw starts good and throttles up well. However, when it's idling it'll idle for 4-5 seconds and the idle speed drops for couple seconds. Does this for a while til I turn it off.
Any ideas how to get this to idle right? H and L screws set per workshop manual.
Thanks
Jerry

 

[Adirondackstihl]

New fuel filter?

 

[jerrycmorrow]

Yes

 

[backhoelover]

pass a pressure and vac test?

 

[backhoelover]

also check the nozzle check valve to make sure it is not leaking by at idle

 

[jerrycmorrow]

Where is this idle check valve you speak of?

 

[backhoelover]

you can see it inside the barrel you know it out from the metering side the carb manual should help. and the walbro manual covers the test. it also covers the capillar covers also they are like a nozzle check valve but on the cheaper walbro carbs. also here is zama dont remember if it covered in the zama manual or not

 

[backhoelover]

if you can send me you emai address. i can send you the testing check list from stihl cover all carbs. purge and non purge. also need to check welch plugs. below is the tech data on that

 

[backhoelover]

you can knock it out from the metering side. into the barrel. sometimes you have to remove a throttle plate to get it out. this could also be a leaking gasket. impulse runs the carb and if it is weak carb will not run right at idle. anymore info just send me a pm

 

[Wood Doctor]

Notice that OP said the idle dropped a little after a few seconds. However, he said the saw's engine did not die. I think I can live with that. Is the world perfect? Give me a break.