guys, what is the life of a glow engine? I have an OS 25 FX that looks fairly beat(varnish and all that) and does not seem to run too well. It tends to cut out with about 1/4 fuel left in the tank.

Its about three years old, seen a fair bit of crashes. I flew for a year, then dind't for another year, and flew all this year. Highest RPM I tend to get is about 13000. Using 80/20 fuel (no nitro, castor oil) and an A3 plug.

been thinking of trying 5% nitro

For what it's worth - Duke Fox said a few years back that 200 hours was a good life expectancy for a good model engine. That's been a while back and I'm sure you will hear from someone that they have an engine with four times that many hours. Of course it's had three new cylinders and pistons, two new cases and a couple of crankshafts. Modern materials have lengthened the useful life of model engines in the last few years. Unless you keep log on all the run time you'll never know for sure.

If the engine turns over freely I would focus on the carb. Take it apart and spray automotive carb cleaner through all the passages. Make absolutely sure the carb and needle valves are clean and try it again. If it does not turn over freely, take the engine apart and check all the bearings and the piston/sleeve for wear. There's not a whole lot to these engines , and you can tear it all down, clean everything, and re-assemble it in about an hour or so.

How long a motor last depends on how you use it and how well you take care of it. If you run it rich while flying and you put in some maintenance of the motor after flying it should last you for a long time. I learned to fly 9 years ago one a trainer that had an OS 40 FP motor on it and it's still running today, the motor has well over 500 flights on it. A friend of mine at the field has an OS 91 4-stroke that was close to 15 years old and too many flights to count, only major maintenance to date was replacing the bearings this year. But if you run the motor wide open and leaned out you can pretty much assure that it won't last long.

Hope this helps

Ken

Hi khozu,

If what you are saying is that the engine runs ok for 3/4 of the tank capacity then, I don't think you have a problem with the engine. That being said when I run into this kind of a problem I disassemble, inspect, clean and reassemble the engine and complete fuel system. I suspect you have a problem with the fuel tank lines. A pinhole in the pickup line (in the) tank will produce exactly the problem you are talking about.


Darren

Re: "Highest RPM I tend to get is about 13000."< this number doesn't tell us anything unless you include which brand prop and which size. I can have a 2000 rpm rpm difference just by changing props. Also consider trying 10% nitro fuel. That will give you more power without overheating the engine. I found it to be a good all around fuel that works well in all my engines. You might also want to consider removing the fuel tank and inspecting it. Fuel that is just sitting can turn gummy and plug lines and the fuel pick up.[8D]

Thanks guys! The prop is a 9x6 Master Airscrew. The engine is turning over completely free. Am going to use some Nitro this weekend! I think since it was my first engine its not been looked after the way it should. Nowadays I run the tank dry, clean it from the outside with a mild cleaner and put some after run oil in there. Hopefully now my engines should last longer.

check your fuel lines and tank!

Counting the number of flights on an engine does little in estimating the number of hours and engine will last. Most flights are in the 10 to 15 minute range. I've had some airplanes that lasted for years and I couldn't tell you how many hours are on the engine. That the planes lasted as long as they did wasn't due to anything but lucky thumbs. Some don't last past the second flight. I still believe Duke Fox had it about right if you add maybe another 50 - 100 hours for modern materials and machining.

it depends on the engine brand a lot also,i say that in general.some of them seem to last forever no matter what brand they are.i have OS,tt,st,mds,asp,mcoy,irvine,k&b and enya.the one that gave me the most problem was the k&b 61 sportster engines,i have had several of those and had to replace pistons liners,i have always used a good after run oil and attribute that to my success,I'm not trying to start a fight with the after run oil that was IMO..lol.someone here said about 200 hours i would agree with that estimate that is an awful lot of flying time if you average that by about 15 minutes.most of us usually fly on the weekends and not every weekend,and about 4 flights a day on each plane we take.i get to fly about 4days a month.that would equal for me to about an average of 8 years if my math is right.i have an os40fp that i bought in 1985 it is still going strong.

Due to the average amount of care, the lack of proper setting, and the occasional crash, though, most model engines are lucky to get past 25 hours or so. That figure was once estimated by Clarence Lee several years ago in one of his RCM columns.

we are fighting two factors i didn't mention....ground and gravity..........

Thanks guys, but the problem just went away. someone hand launched it really badly(crosswind in a really HEAVY wind) and the model was a complete wrtie off! The needle valve broke off, the throttle lever broke off, etc etc.....I gues it was fates way of telling me to move on to a new model!

Re: "I gues it was fates way of telling me to move on to a new model! " < Works for me. I always get excited about a new model. I once said that I would quit buying after 3 models. I am up to 12 now so............[8D]