Motor is 1980 Eska 3.5hp with Tecumseh 2-stroke. Starts and runs fine at 'start' throttle position and below. Misses consistently at anything above 'start' throttle position - sounds like its missing on every other stroke. Runs the same in a test tank and on the river. Engine smokes when it's missing. If I cut off the supply of gas to the carb while it's running (missing), it will continue to miss for a while and then will run beautifully smooth for a short time right before it runs out of gas.
I'm using fresh ethanol-free gas with 24:1 oil mix. I've cleaned and rebuilt the carb, checked the points, and replaced the condenser. I've tried higher and lower carb float positions. Motor has good compression. The exhaust chamber has been checked for obstruction.
This is a low hours motor was stored for several years until I purchased it late last year. This was a virgin motor at that time - not one bit of paint missing from anything under the hood - never tampered with. The carb has an idle mixture adjusting screw but no high speed mixture adjusting screw.
To me it seems like it is getting too much gas at higher throttle positions but I can't figure out how that's even possible.
ANY suggestions/ideas are welcome!
I'm using fresh ethanol-free gas with 24:1 oil mix. I've cleaned and rebuilt the carb, checked the points, and replaced the condenser. I've tried higher and lower carb float positions. Motor has good compression. The exhaust chamber has been checked for obstruction.
This is a low hours motor was stored for several years until I purchased it late last year. This was a virgin motor at that time - not one bit of paint missing from anything under the hood - never tampered with. The carb has an idle mixture adjusting screw but no high speed mixture adjusting screw.
To me it seems like it is getting too much gas at higher throttle positions but I can't figure out how that's even possible.
ANY suggestions/ideas are welcome!