Hi everybody, brand spankin new to RC and I decided to get a plane. Well, I bought mine from a friend, had for a week and broke the original wood engine mount[:@]. This gave me a chance to test out the engine on a test stand to see how much power it had with out breaking the plane any further. On the stand it worked flawlessly at all speeds even to the smallest opening I could make in the carb. As soon as I replaced the engine on the plane the engine would quit as soon as I took the glow starter off. I'm thinking that I need a new plug ...any advice from you vets? Thanks a bunch!!!

easy way to find out, replace it and see if that solves the problem.

startting problems are a good indication that the plug is no good.

Try letting the engine warm up a bit with the glow clip still attached. This may help a bit. You will probably have to replace the plug soon though.

Very often a new engine will eat a glow plug or two during breakin. A new engine does produce a few metal particles that can foul up a plug.

Or the glow lighter might be dead,mine was yesterday after several good starts,you can take yours out and see if it will glow.


*OUCH that darn plug got hot* [X(]

GOOD glow plugs can last a LONG time... if you properly tune the engines. I had one plug outlive 3 engines, from break-in to worn out completely. (unfortunately they don't make that plug any more. Or it would be all I ever bought.)

Never let the engine run lean and you shouldn't have problems if you are using a good quality glow plug. The O.S. plugs seem the best of what I can find now. (Up to 10 gallons through a .40 size engine per plug.)

What are the symptoms of a faulty/marginal glow plug?

The usual symptoms of a bad plug are the engine slows down when you remove the ignitor battery and/or the engine won't idle without dying. Just because it glows doesn't necessarily mean it is good. If the filiment has been contaminated it may still glow with external power applied but, the alcohol does not make enough contact with the element to permit the catalytic reaction required to keep the engine running.

Hey thanks guys! I really appreciate all the feedback. Being a newbie to glow rc airplanes, I didn't want to screw up my plane anymore than I already have. I especially don't want to mess up the engine, as the guy that I bought it from told me that the adjustment screws(high and low idle?) are set perfectly.

The engine idle problems are usually bad fuel-air mix.. not a bad plug. The description gibven of a plug starting to go bad (slowing down when the ignitor is removed) is typical of too rich a fuel mix at idle.

I've never had a plug that glowed with electricity applied that wouldn't properly run the engine. (in over 30 years of dealing with glow engines.)

I have only had one plug that would glow and not run the engine in 10 years. Don't hold any one thing suspect. What you said is going on could be bad fuel too. I had some fuel that was about 7 days old from the hobby shop. I don't know if I left the lid off too long or what, but Glow Fuel has the natural ability to absorb water from the air. (That is why you use after run in an engine before you put it away -- stops the rust and crud as well as other things) If your fuel is bad your engine may not run after you take the battery off the glow plug. If you change the glow plug and still have the same problem, drain the tank and get new fuel.