Hi Kraiuth.

I have a PST 600R installed in a BVM Balsa bandit. I purchased it from Rene of Galtech NZ. The engine is over 3 years old, but is not used that frequently, it has some 10 hours runtime. Up untill now, it has been performing faultlessly, and pushes my 21 lb bandit around like a much bigger engine.

However, this weekend it developed a problem. When ramping up from idle, it "coughed" with a loud bang, and flamed out the exhaust. This happened twice.

The first time was on the ground while doing a ground check from idell to full throttle. It happened as it was acceraring past 80,000 rpm.. After it went bang the exhaust note changed and I shut down the motor for safety. After it cooled we checked everthing over, found no obvious faults. We restarted, and it operated correctly, so we went flying.

On the second flight after this, I was on finals for landing when I opened the throttle from idle, (as I was a little short), when it happened again). I shut it down immediatly as I could see flame out the exhaust.

There is no obvious fault with the engine, it turns freely and the pump seems to be ok. The air temp was about 20C, and we would be close to sea level.

Can you help with any suggestions to help diagnose this problem, or should it be returned for service.

Thanks in advance.

Roger P