Hi there

I have a new OS 91FX. Have about 30 flights with it and have run about 1.5 - 2 gallons throught it. It runs very nice.

Some flights ago the engine died because it had ejected the glowplug! Well... I though... I should have checked that it had been tightened... and then I installed a new one, and even had a buddy check that it was tight enough. 3 or 4 flights later, it did it again! Unfortunately in a KE in fairly low heigh, and the deadstick was far from perfect, with lots of repairs ahead.

The threading in the engine looks perfect, and a new glowplug seems to secure tightly. I am using OS 8 glowplugs and 10 nitro / 15 aerosynth, if these informations is of help to give any pointers to solve the problem. The engine is running very clean and responds to throttle quickly, idles very stabile and draw a slight white line of smoke when running above 1/2 throttle.

Thanks

Ejecting glow plugs happens when the plug's just not tight enough, or the threads are defective/damaged to the point that they won't let the plug stay tight. The only solution is a new cylinder head or possibly rework with the installation of a heli-coil insert.

Even if the threads look good, they may still be deformed enough to not allow the plug to stay tight. The threads in the glow plug hole can become damaged from over-tightening the plug, cross-threading the plug, overheating of the engine, dirt getting in when the plug's installed, and so on. The same things that can damage threads in any type of bolt/nut installation.

Hi Bax

Thank you for the quck reply. I have been carefull not to overtighten the plug at any time. And installing it in a clean environment, turning it finger tight before using a wrench.

I will tighten it a bit more next time, and if it still happens send the engine in for service. The threading seems ok when turning the plug, but could the threading be faulty from the casting?

Might catch someone I know using epoxy to put these babys in..