Hi everybody,
This is a friend's engine that it has been giving problems for a while.
At the beginning it was the typical os46 tunning problems, but lately it just doesn't want to get airborne.
It' start with no problems but as soon as the head starts to rev up it just quit.
It had an OS#8 plug on it we decided to try a different plug I happened to have an Enya #3 with me, we put it on and taa daa! no more problems, or at least that's what we thought.
One flight later and then same behavior again, just quits when revs up and the heli is about to get off the land.
Any suggestions please????
He refuses to use my mallet to fix it
Fernando

You should take the head off and check the cylinder liner for peeling. I had this happen to me. When the plug got coated in nickle debris, the engine wouldn't run. When I changed the plug, it ran well for a while and the same problem occurred. I took the head off and noticed the liner nickle had peeled.

I'll take a look at that.
Funny, when we swap the plug I noticed the filament on the one we got out that it was "fatter" like some material welded to it.
Then we run the new plug (Enya #3) and worked for one flight and that was it.
He was here last night and we took the head and liner out the plug did look ok this time I tried with the hot shot and seems ok too (I know once in the engine and with the cylinder pressure it might be different) but I didn't check on the liner for peeling.
I guess that's the next step.

You may also want to check the bearings for corrosion. Corrosion can "kill" an engine quickly, and a short glow plug life is an indicator. Also check for fuel contamination, check the fuel system and fuel tank. You can have nicely-filtered fuel going into the tank, but if the tank is contaminated, you'll have a problem. Water in the fuel can also cause plug problems.

And the winner is...!!!!
BAX!!!!!!!
New bearings in and the problems are gone!
Thanks everybody for chipping in.
Fernando