I hope this is the right area for this one. I have a couple Tower Hobbies 75 engines.....one brand new, never run, the other is giving me fits, again. It will start, runs at high idle, transitions good to high speed, but when returning to idle it will continue to run at about 4500 rpm, will slow if i push in on the low speed screw. Additionally, are there any extensions to move the muffler away from the side of the aircraft, say 1/4 to 3/8 inch, that goes between muffler and head of the engine?

Thanks,

Clint

While this is the O.S. support forum, we do service the Tower engines. Likely, the carb's not quite set correctly. Start out with a super-rich idle mixture setting and a very rich high-speed needle setting. Start the engine at part throttle and open to full. Get the high-speed needle set correctly, first. Then retard the throttle and adjust the low-speed mixture. You should be able to work the mixture and throttle opening down to a point where you can get a good, reliable idle at 2,00 RPM or lower, and still have good acceleration.

There are no additional extensions for the muffler, but they are easy enough to make from bar-stock aluminum.