I have been training since may about to solo. I have a os fxi engine which has been running great, my question is does any one change glow plug regularly or if it ain't broke don't fix it.

You should keep a couple extra plugs on hand. You can never plan on when one will blow. Usually from running and engine to lean but they do wear out. If your usuing a power paner or a glow starter with a meter guage on top of it, that will also tell you if your plug is bad because you will not get a reading from it.

Its rare that it blow in flight but does happen. If it goes, you'll know it when you try and start the engine. The engine may also start but run bad or won't stay running.

I think your correct about the "Ain't broke don't fix it" I woulden't mess with it until you start getting erratic engine problems that don't usually happen. I have an Alpha trainer that has about four gallons through the evolution .46 engine and I have never replaced the glow plug yet. I also have an HPI Savage monster truck that has the original plug in it and it has more than 4 gallons on it also. The hardest part of a glow plugs life I believe is in a brand new engine or if you tend to run an engine very lean.......I think.

Hope this answers your question.

Joe

If your engine is over-propped you'll eat through glow plugs too! Increased nitro.......cooler plug. Decreased nitro/increased lubricant......hotter plug. Have a good one.
xs

Once an engine is broken in, glow plugs seem to last for a very long time, sometimes well over a year or two. However, if you get a lean run or use excessivly high nitro, they can burn out on the first flight. Often, when breaking in an engine, a glow plug will fail, probably due to wear particles from the breakin fouling the plug element.

I agree with what's been said. Don't worry about your plug until you have trouble.

First sign is often when starting; the engine will start fine, but it will quit or the speed will drop off when you remove the glow ignitor.
Dennis-

When you DO buy replacement or spare plugs, get the good plugs, not the cheep plugs.
Just like props, you will get a noticeable difference in performance between manufactures but with glow plugs that also means longevity.

I used to buy a half dozen $2.95 plugs at my LHS and would go through them in six months, and now a $6.95 Enya #3 or a OS F Type plug will last me that long in 2 or 4 stroke engines burning Powermaster YS-20/20.
Remember, you can use 4 stroke plugs in 2 stroke engines but not the opposite.

Experience is a wonderful thing.

P.S. A good friend will keep you from doing stupid things... alone.

In most of my 4 strokes, I have found that the Fox Miracle Plug works as well as any other and is somewhat less expensive.

Would an OS F work in an OS 46 FX or AX. Does it have an idle bar. I am just curious. I am running the engine inverted and wondered it it might make it run a little better than a OS #3 or #5.

I don’t remember changing a plug in the past 7 years. But my engines are not run lean and are well broken in (maybe worn out).

Not entirely on plugs, but I'm a little confused about a couple of posts above.

One says higher nitro, lower running temp, and another says lower nitro, lower temp. Which is it?

I'm particularly interested because I've just taken delivery of a couple of RCV 60-SP's which I believe run hotter than most engines, but the recommended fuel is 10% nitro. Maybe I could increase the nitro and keep the temp lower, but the manufacturer recommends 10%.

Can anybody help?

On the subject of plugs, I have about three gallons through one engine with no change of plug.

In response to his original question, "How long do glow plugs last?"

Answer: Usually a minute or two shorter than you need them to last!