Engine cleaning

Tell us what you do to get the best performance from your engines.

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Ed Kettler
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Engine cleaning

Post by Ed Kettler »

A buddy of mine gave me an OS 40FP that was off his trainer. He actually gave me the radio, servos, fuel tank and the firewall forward, as this was all that was left of his trainer[:I]

At any rate, the engine appears to be very low time, and other than a bent needle valve it appears to be undamaged. The main problem is that it has sat around for 5+ years and barely turns. I took the head and backplate off, squirted it full of wd40, and it does turn by hand with a prop, but with a ton of friction. There appears to be brownish gunk in the vicinity of the prop drive nut, and inside the crank case. Is there some easy way to clean up this engine, short of disassembly? Would soaking it in fuel clean up the old, dried on fuel?

Thanks!
Ed
Hat Trick
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Post by Hat Trick »

Put it in a old crockpot with some anti-freeze. Let it cook for a day or so on low heat.

Works great!
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lightning
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Post by lightning »

Hi Ed, don't forget to remove the carb too so you can take the rubber "o" ring off its base. A/F will eat it. The rest of the carb is OK to cook.
And remember not to cook food in the Crock-pot ever again - very toxic!!
Good luck
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Ed Kettler
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Post by Ed Kettler »

Well, hmmm, after a bit of disassembly and some cleaning and oiling, the engine now turns with very good compression, and would probably start ok. The bad news is the carb barrel is stuck, and it looks like OS hired King Kong to put the carb screws in, as they won't budge, even using the Japanese screwdriver. Any techniques for loosening these screws? If I can get the carb off, I can at least replace it if it won't unstick.

There are two small adjustment screws on the arb. One, mounted horizontally, looks like it adjusts a bleed air hole, so I think that is the idle adjustment. Another screw comes in vertically. What does that one do?

Thanks!
Ed
Don Pruitt
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Post by Don Pruitt »

Ed
You are right, the horizontal screw is an air bleed and the vertical screw seats down in a slot in the carb barrel. Remove this screw to remove the carb barrel. To loosen the screws I would try first removing the plastic throttle control arm and then using a propane torch, heat the carb area to loosen the screws. You will have to get the cast aluminum hot enough for the metal to soften then the screws should come right out. Let me know how you make out.

Hint: If you ever break a plastic throttle control arm you can make another from a servo control arm.
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Ed Kettler
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Post by Ed Kettler »

Thanks Don,

I'll give it a try tomorrow. Maybe teh heat will loosen the carb barrel too.

Ed
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boiler
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Post by boiler »

I've been successful by grabbing the sides of the screw with a GOOD pair of pliers to crack the screw loose. Quick and no heat required.
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Ed Kettler
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Post by Ed Kettler »

Bob,

That worked great! A trip to the LHS later in the day and some application of heat loosened up the carb barrel, so everything has been disassembled, cleaned, oiled and put back together. Now all I have to do is build an airplane for it!

Thanks everybody for all the input!
Ed
sgilkey
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Post by sgilkey »

The crock pot method works well for baked-on goo (i especially like to clean gooey cylinder heads as I have convinced myself that would help the engine run cooler). For "stuck" engines, sometimes just a good soaking in glow fuel will loosen them up, often it is just congealed/stiffened oil. Put em in a cup full of fuel and let em soak, turn it over once in a while, and things will often free right up! On the OS carb screws, pliers work well, vice grips even better!
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