I have an old used gas engine .
when i fire it up it starts. idels nice . accelerates nice up to about half thortel any more gas and the engine starts to hunt .
any ideas was woundering if it's a carbereter problem or a compression problem.

by hunt i guess you mean die try leaning off the top end needle

What motor is it? Real gasoline or glow?

I just had the same problem with an engine that had been sitting for several years. turned out the needle valve was just set really rich. try leaning it out