Saw cuts out when revved to full throttle...

[knockbill]

Its an old Homelite 24o, 16" bar,, kept well serviced,,,
Back story,,, starts easily, and ran well until it was shut down to refill tank a few times... Then wouldn't start again until it was cool... Yesterday, it started right up but at full throttle, it will stumble and die unless I feather teh throttle,,, it will idle fine, but wont stay at speed to cut...
I checked teh plug and spark when it was hot, and seems to have a good spark with or with out teh plug in...
Tried to adjust teh carb and found that it will start easily, run up to maybe half throttle, then start stumbling, and will die if it isn't feathered or return to idle... Also,, the hi speed jet does not affect carb adjustment at all,,, it runs teh same with teh hi jet closed or open way too much!!!!
Today I disassembled teh carb, cleaned teh jets, needle and all passages, and replaced teh valve diaphram,,, checked piston/cylinder for scoring, and its smooth... It runs teh runs teh same after reassembly,,, no HI speed adjust, and stumbles when revving... It has a Walbro WT 6A carb...
Any other ideas?
Thanks...

 

[Wood Doctor]

You might be clogged up on the exhaust port. Remove the muffler, clean the spark screen, and if you have to, drill a 3/8" hole in the muffler's front end panel. I did that with a Homie Timberman 45 and it made all the difference in the world. Just an idea.

 

[Tree climber Confederate]

A bad coil can still look pretty good though. ‍

 

[PV Hiker]

History on fuel filter, air filter? Fuel being used fresh?

 

[DaddyFlip]

Must be something wrong with teh the.

 

[knockbill]

Hey guys... thanks for teh quick replies!!!! Not muffler/carbon, checked it yesterday when I checked piston from exhaust port... Clean as a whistle, I modded teh muffler when I got the saw, cut really strong all teh time, till this problem...
New fuel,,, just cleaned air filter... And It was teh fuel filter!!

Thanks for reminding me of what I did to cause it,,, so you can all get a good laugh!!!! I accidentally put oil in teh fuel tank, a bit ago, thought I rinsed it all out before running it but the filter must have gotten saturated... I just rinsed teh tank again, and replaced teh filter from another small Homie,, exact same filter... Think I'll order a bunch of them just in case I do it again!!!!

Only thing I never liked about this saw was teh oil and fuel caps are teh same color... Not sure if that will take care of the hard restart when hot, but we'll see!!!
Let the flaming begin!!! Just remember,, I'm an old guy, and the senses are going quickly!!!
I really appreciate the ideas/help...

 

[Wood Doctor]

Hey guys... thanks for teh quick replies!!!! Not muffler/carbon, checked it yesterday when I checked piston from exhaust port... Clean as a whistle, I modded teh muffler when I got the saw, cut really strong all teh time, till this problem...
New fuel,,, just cleaned air filter... And It was teh fuel filter!!

Thanks for reminding me of what I did to cause it,,, so you can all get a good laugh!!!! I accidentally put oil in teh fuel tank, a bit ago, thought I rinsed it all out before running it but the filter must have gotten saturated... I just rinsed teh tank again, and replaced teh filter from another small Homie,, exact same filter... Think I'll order a bunch of them just in case I do it again!!!!

Only thing I never liked about this saw was teh oil and fuel caps are teh same color... Not sure if that will take care of the hard restart when hot, but we'll see!!!
Let the flaming begin!!! Just remember,, I'm an old guy, and the senses are going quickly!!!
I really appreciate the ideas/help...

Classic case: when there is possibly a fuel delivery problem, start with the fuel filter and work your away back to the carb. I guess I figured you had already done that. My error. A really bad fuel filter even prevents starting and idling or allows starting and then dies on any trigger pressing.

 

[knockbill]

Yep,, It was a new filter,,, and I did think about checking it in the beginning of the journey,, but I started to try to adjust it out, and forgot all about it!!!! You'll see how that happens when you get old!!!!
That old filter had so much oil in it, I couldn't blow air thru it, still cant image how that saw started, let alone get to about half throttle before stumbling... Sad part is, I'm really starting to forget all teh tricks, and sequences I knew about trouble shooting everything over teh years....
Stay tuned,, I'm sure another similar story will happen!!!!!

 

[Vintage Engine Repairs]

Exactly the same problem with a different saw, I put it down and haven’t come back to it yet, I think it’s now down to either the manifold or seals. If it’s not them, then I’m lost as to what it is.

 

[knockbill]

Yep,,, I always think its teh worse case,,, usually turns out to be something simple I forgot about or missed!!! Good luck!

 

[Wood Doctor]

Changed the fuel filter in a Blue Max today and that fixed it. Engine would start and then die when it slowed down to idle. You could repeat that 10 starts and runs in a row. Now it runs flawlessly.