I have a Turnigy 50-HP engine that refuses to go over 5,000 rpms. The owner could not get it to run properly so he gave it to me as part of a trade.

The engine used to run strong, then one day it would not start. He could not figure out why, so he got a new carb from Hobby King and a replacement TGY ignition. The carb looks like this one from HK's website.

With the needles set at approx. 1.5 turns out it starts easily, idles nicely, and revs smoothly up to 5,000 rpm. Above 5.0 - 5.2k rpms it dies. Richening the needles does not help. I am running a 22 X 8 Xoar prop at 32:1 gas/oil mix (Pennzoil).

I replaced the ignition with a spare RCGF module I had available, but the problem persists.

I understand that this is a XYZ 50-HP engine re-branded by HK. It is a rotary valve engine.

Any ideas or suggestions would be appreciated.

Thanks in advance,
Ted