I have an OS 18 and its been doin great. But now its burning out plugs. Not just every once in awhile, I can't even get through one tank of gas!!! I tried a few diff things- types of plugs, richer settings, leaner settings and still nothin. The only thing that cam close to helping was the rich setting but it ran like crap. Any body have any probs like this before??? If so whats goin on? And how do I fix it?

what plugs are you using? OS .18 stock plug is an OS #8. I have an OS 12 CV-R that has 5 gallons thru it and i'm on the same #8 plug.

Are you sure it is your plugs that keep going bad? Make sure your ignitor is charged, then take the plug out and see how bright it glows. Check a few of them, and it would be good to compare them to a new one.

First off, yes I'm sure it's the plug. Apon looking at the plug after use it looks "melted" but still glows a little. I have tried 3- OS 8's, 2-OS A3's, 2-OS lc3's and 1-FOX plug. None of them lasted longer than one tank of fuel, most not even half a tank. They were all brand new plugs as well. I'm REALLY stumped on this one.

Have you ever checked your temps right after your plug goes out?

My best guess is bad tune, possibly caused by an air leak....

Temps are fine, stays between 225 and 240. I had thought about an air leak and checked the backplate,carb and head and they all seem fine. Maybe I should use some sealer on the backplate and carb and try that. Any thoughts?

Running it too lean. Bet the top of your piston shows detination(pitted)

Nope, no pitting in the head either. I tried running it richer and it ran like crap. No power what so ever and that was only a 1/4 of a turn richer.

Bad fuel maybe?

I was just going to ask what kind of fuel you were using. How much nitro % and oil content was in the fuel?

Every thing I have read about this problem they say to lean, air leak or bad or poor fuel. [8D]

I think it may be an air leak in the front bearing. I pulled the motor to check all seals and when I turned the crank by hand I felt a slight tick. Pulled the crank and a bearing shield came out as well. [:@] The fuel I'm running is 15% and 16% oil with 20% of the oil being caster. The fuel works fine in my other gt so I don't think its that. Either way I think I voided the warranty by pulling the motor apart so I may end up just buying another one or a different motor because the parts for this thing are outrageously priced.