I used to fly RC (about 15 years ago) but marriage, a career & kids pushed my hobby to the back burner.

Now I would like to get back into it with my sons. I have a .40 sized trainer with a OS 40 FP that is pretty gummed up. The shaft turns freely, but the carb is sticky.

what can/ should I do to free up this little engine for use again?.....or is it worth the effort vs. buying a new one for around $60?

thank you for your help.


Tom

I can't see any reason why you can't get the FP back in the air. There are several things you can do to un-stick the carb on your motor. Squirt a bit of WD-40 in the throat of the carb and let it sit, that should free it up.

Good luck, and welcome back to the addiction.

Ken

If you have some antifreeze try soaking the entire engine in the stuff.
If you can warm it, even better.

Search for, "crock pot antifreeze". You'll find lots of info about cleaning up old castore oil off engines.

I'd try to bring it back to life.

All are good ideas. Another one that works well is to soak the engine in fresh fuel.

fuel or denatured alchohol will remove the stickiness then oil it up with after run oil or marvel 3 in 1 oil.to keep it freed up.there are no ball bearings in the fp series to go bad so it should run fine after freeing it up.there is only one screw that holds the throttle barrel in the carb body.you can always remove that screw and the barrel should slide out the exhaust side.just scrub everthing with an old tooth brush and alchole to remove old gummed up oil and dirt.then oil and reassemble should take no more than 30 minutes and should turn as free as new.good luck

I got back in last March after a 15-yr hiatus (same excuses) with a 40 FP. A little WD-40 got it running, but it never ran great and after about 30 flights, resulting in about 15 deadsticks, I replaced it with a used 46 LA. Bolted right in, even used the original muffler, and the plane feels twice as fast. Hope you have better luck with your engine.

As Britbrat says, soak it in fuel for a couple of hrs, The alcohol will go right after the congealed castor. An old tooth brush or brass wire brush will take off the burnt stuff on the muffler too. Make it look like new

I've put several engines back in service over the last year and a half. Parts that would move, even the slightest bit, were loosened up in no time with a bit of alcohol. When I encountered parts that were completely stuck, such as a couple carbs, I put them in the oven at about 350 for 10 minutes or so. The heat loosened up the gummed castor enough that I could move the part so I poured in some alcohol and move them. The alcohol quickly cleared out the gummed castor. One other thing to do is to remove the needle and make sure the spray bar is clear of gummed castor. Once the alcohol was running clear, meaning I got out all the gunk, I put the engine in the oven for about 10 minutes to evaporate any remaining alcohol. Then I removed the engine, lubed it with machine oil and put it in a plane to fly. Every one has worked great.

I've had pretty good luck with the crockpot and antifreeze method of cleanining, but that carb might be a good idea to make sure it's cleared out. I actually have a used FP without a muffler that I recently cleaned, replaced the screws, seems fine, just haven't run it yet. From what I'm told, that FP is supposedly a good engine. I also have wondered the amount of time and money I'm investint is worth it. For $55, you could have a nice new TT GP42, that I've have had good success with. It's a very close call. Work on it make it work, or just buy a fresh new engine. Do your tests, and make a decision. If it doesn't work out for you, don't waste any time. Get into a new engine. Time is money and certainly the frustation factor should be taken into account. Sometimes it is just best to get into a new motor. Good luck. Tom