Super Tigre G90 won't idle.
 

Bax,
I read your sticky on how to adjust ST engine. I have done all that but the engine won't idle.It is a G90 and runs just fine except when I throttle back the engine dies abruptly when it approaches idle speed. It acts like the carb barrel has been suddenly closed although there is still about an 1/8" opening in the throat.
Any suggestions?

Regards,
doubledee

I have also noticed when I try to adjust the low speed needle the throttle assy moves laterally slightly causing the engine to die abruptly.

RE: Super Tigre G90 won't idle.
 

Put in an OS F plug.

Paul

RE: Super Tigre G90 won't idle.
 

It's normal for the carb barrel to move a bit when you try to adjust the idle mixture. However, the engine should still run when the throttle is still opened about 1/8". You need to make sure the engine has the idle mixture set wildly rich. That is, too rich to have any hope of idling. Then you must start at part-throttle and get the full-throttle mixture set. If the engine's broken-in enough, you should then be able to retard the throttle a bit at a time and work with the idle mixture. It will start to have effect below 1/2-throttle or so.

After all this, if your engine has more than a few hours' worth of full-throttle running, and will hold a top-end needle setting quite well, then there could be a problem with the carburetor. However, don't discount the fuel. We'd recommend a fuel with about 10% nitro or so with a synthetic/castor blend in the oil mix. Some blends of fuel, or fuels that have been sitting around and not well sealed, can cause difficulties.