Hi All

This is my first posting to this group and I hope that someone can help me. I have an MDS 38 Pro engine and am having difficulties with keeping the engine running, it will start fine and work well with a good transition from idle to mid revs. However when I go from mid revs to full throttle the engine peaks for about 2-3 seconds then stops. Does this mean that the engine is to rich and if so does it mean all I have to do is lean the main needle out. answers on a post card would be nice. Also what is the best way to check to make sure that the balance on the plane is correct.

Well for the needle valve you need to be at full throttle when adjusting it. I don't have any MDS engines but sometimes this happens. Just try to keep it at about 1/5th throttle and let it warm up, it should not do that after a while. For the balance, you need the manual, check the manual for the balance then mark it on the wing on the upper side of the wing and turn it upside down and hold it there with ur fingertips. If it is a trainer you don';t really need to turn it upside down, just pick it up from underneath the wing by the spar. If you need weight either way, shift the batteries and RX, or add lead
Victor

Victor

Thanks for the help i will try this when i get home from work, Will let you know

Cheers
Sherpa

If the engine runs fine from idle to mid-range, then quits when you push full throttle, it sounds like it's much too lean to me.

If it was too rich it wouldn't "peak for 2 to 3 seconds" before it quit. What's happening is it peaks for a short time, then because it's too lean, it overheats expanding the piston causing it to cease. (NOT a good thing!)

I'd try richening the top end by at least 1/2 to 3/4 turn.

I agree, it sounds too lean on the high end.

(though I disagree on why it stops. If it was a ringed engine, DB, I'd agree, but for an ABC, the liner expands faster than the piston resulting in a loss of compression. But either way, the engine probably just ran out of fuel before either of those things could happen. Minor point though, and doesn't matter either way).

Hi Sherpa:

Welcom to the club!

It seems like you have the same problem I had this weekend when I was breakin-in my new Tower .75. After all it was running too rich.
To simplify my life I went to basics - the manual. I set the niddle at recommended starting position and had no problem starting it or tuninig it later.

Good flying!