I have a gas engine that runs perfect, but it seems to hit full rpm at half throttle any suggestions?

Open the high speed needle about 1/8 turn and install a smaller prop.

change throttle exponential or change your throttle curve

When you say "half throttle" do you mean when the transmitter stick is at a half or when the carburetor is half open? The fix is dependent on your answer.

Regards,

Richard

It's both. I set up linkage same as usual to go full travel, but when transmitter stick gets to halfway and butterfly halfway, engine is at top speed.

Well most gassers DO hit close to full power with the throttle butterfly about the halfway point, not much left in the last bit of travel. They are also really sensitive coming off idle and the combination of those two is why you see folks talking so much about throttle linkage geometry as well as some use curves to help give you either a more centered throttle stick at half engine power, or achieve a better control of low RPM situations, or both.

There are also several other tricks you might want to try, check the forum threads with the search engine for more ideas....

Short servo arm and long throttle arm.

Thank you all for the input it is greatly appreciated