ORIGINAL: jaka
Hi!
Follow the KISS principle!
Get rid of the pump!
Get rid of the fuel valve!
Mount the engine on its side so that the carb sits right compared to the center of the tank!
Keep it simple stupid! +1
You hit it right on the head my friend. I second getting rid of the pump and fuel valve. Re-mount the engine on its side so that the carb sits right compared to the center of the tank. Remember folks, the more bells and whistles- and the more people complicate things, the more things can go wrong. And like Uncle Murphy's rules said, it usually does.
ORIGINAL: K-Bob
OS 91FX two strokes had a design flaw that would produce symptoms similar to what you are descibing. Make sure you install the fix available from OS. IIRC it repositioned the remote needle valve.
Correct. I was lucky enough to get a later model of the O.S. 91FX-ringed and mine didn't have the problems. I think I got mine 1 year or slightly less before Hobbico decided to discontinue the model. I guess the major flaw was the back plate design from what they told me.
Pete