Hi, I recently bought a p51 mustang PTS MkII, to replace an old Alpha trainer I had last summer. I have not yet flown it, Im going to find an instructor first. But I have been practicing taxiing around the yard a lot lately. The engine had been working great. But one day I couldn't get it to start. It won't even fire, no matter how long I leave my electric starter on it. I have not messed with the needle valves at all, they were supposed to come preset from the factory and the engine seemed to run fine, so no reason to touch them. I checked the voltage on my glow plug igniter, it was about 1.45 volts after an overnight charge, seems reasonable. The plane is fueled, and I have been using brand new fuel (15%) instead of the old fuel from my alpha last summer. I can't find any holes in the fuel lines or tank. The only thing left that I can think of is the glow plug itself. The engine has probably been run less than two hours all together though, so it seems kind of early for a glow plug to die. How long do glow plugs typically last?

I think I bought a spare glow plug for my alpha last summer if I can find it. It was an OS #8 I believe. If I find it, can I use it in the mustang's evolution trainer power system? Also, I believe I have a glow plug wrench somewhere with all the other stuff I have left from my alpha. I assume switching the plugs is pretty simple right? Unscrew the old one, screw in the new? Does it need to be in really tight, considering the extreme pressure in the combustion chamber?

Also, I have a voltmeter, is there a way to check if a plug is bad without removing it?

Thanks for your help guys!

Glowplugs sometimes last a few days, sometimes a year or longer. If you have fuel reaching the engine, heat in your igniter, and you're using a an electric starter, then the glowplug is the only culprit left to keep it from starting.

To replace it, you do just unscrew it and put the new one it. Make sure the little copper seal goes on. And just snug it down. You're screwing into aluminum which won't take much torque. All you need to do if put a little tension on the seal; the threads do the rest.

Remove the plug, connect it to your glow driver and see if it glows. If it doesn't, something's wrong - either the plug is bad, or it's not getting current from the glow driver.

If it does glow, It could still be bad, although that is pretty rare.

To put the glow plug back (Or put in a new one), first make sure the copper washer is there and tighten it just past "Good and snug". Tightening too much can strip the threads in the head and then you have real problems.

Yes you can use the OS #8 plug. In fact, I would recommend it. One of the best on the market. You can use a regular socket wrench to remove the plug. I never use a plug wrench, becausea socket seems to seat better on the plug. When replacing it, DO NOT over tighten it. You only need a snug fit, and a little pressure on a ratchet is plenty. Make sure you have a plug seal ring in the plug hole. They usually don't come out when you remove the plug, so you can just re-use the original. Regarding checking the plug in the engine, you could use an Ohm meter, but Iwould just remove it and put the glow battery to it while holding it in your fingers. Just don't touch the element. You may damage it. Glow plugs should last many hours, but you might have a cheap one. They don't live long. Always use good quality plugs.

pmw

Ok, thanks for the quick replies. I will try testing the old glow plug and replacing it, and get back to you if that doesn't work.

yes you can check for continuity of the glow plug installed...by using the Rx1 scale on ohms...one lead to the ceter post of the glow plug..make sure you don't touch the sides of the plug...the other lead to the engine case...should show some resistance as your reading through the coil of the glow plug...not always accurate as the coil can open and short to case reducing the resistance of the plug and its heat...if your open the plug is bad....
if you have the standard engine with your PTS it's an evo.......vibration from taxing around can effect the mixture settings on those engines....there is a blue lock that will move around....
It would be best to wait till you get with your instructor to show you how to remove it

also you really need to let someone tune your engine before you keep running it.

The PTS engines are known to produce metallic flakes during their first few break in runs.

These particles are fairly small and feel like goo when mixed with glow fuel oil. The particles are responsible for the famous "Grey Goo" that the Evolutions are known for.

The goo goes away after about a gallon of fuel run through the engine.

One side effect of this stuff, is that it will stick to the platinum element in the glow plug, causing it to either burn out or not remain lit evenly.

Grab yourself several spare plugs and be ready to change them out.

Once you're on the second gallon of fuel or so, you'll not have to change plugs with any frequency.

cjmdjm

I noticed you said you had been "taxiing around the yard a lot." If your yard is paved , no problem. But if your yard is dirt (maybe dusty dirt), you may be ingesting dust into your engine. I'm not saying that this is your problem, just that it is not a good idea to get dirt sucked into your engine. Your engine will run better, and last longer if you taxi on the lawn. Didn't mean for this to sound like a lecture, just didn't know if you were aware of potential damage by dust. Good luck with your engine.

Lm