OS46 LA question
 

O.K. I have been out of the RC airplane for about five years and now getting back into it. I have a OS46 LA that only has six tanks of fuel through it and that last flight was five years ago. I did put after run oil in it at the time, but it has set ever since. Now that I look at it I have found it has locked up pretty tight, very hard to turn by hand. If I tear it down and clean it up good any chance of it being able to be used again or should I just make a good paper weight out of it.

When I did fly it I always had it running very rich, but just not sure it worth buying all new gaskets and trying to play with it.

Put some oil in it and gently work it in....there isn't much to go wrong in those engines. The "bearings" are actually bushings so chances are it's just stiff from sitting so long. I had a Saito .72 that was very stiff after approx. 5 years of hanging on the wall nose down. I just worked the prop back and forth a bit and it eventually loosened up. That engine runs like a top now.

CB

I got an engine running perfect that sat for 15 years. I took off the head, muffer, and carb and let it soak in fuel for a few days.

Fuel and/or heat. If you've got a heat gun, shoot it at the head and the carb being careful not to get any plastic parts too hot. Or you can take the glow plug out, shot of fuel down the top, take the back plate off, shot of fuel in there, shot of fuel in the carb, open is best, but closed is ok, just let it soak in. Or you can just dump the whole thing in some fuel overnight. It'll free it right up and it'll be good as the day you left it.

DO NOT DISMANTLE!

Dunk it in kero, glow fuel, or gas overnight or longer.

Remove plug drain and turn over a few times to clear.

Refit plug and check that it turns before applying starter.

It will run just fine. Just gotta get rid gummy oil.

Agree but I don't always bother soaking it in fuel, if I have a tub of fuel on hand then I will but just pulling the glow plug and putting some fuel in the cylinder then heating the engine with a heat gun and rolling it over will loosen it up. Then just start it, it should run fine. I put on a spinner nut and roll it over while it is hot. Once it fires up and gets to operating temp it will blow out all the nasty old castor.
I have had LAs under the bench for years and done it like this. There is nothing in them that is going to get boogered up.

Break out the fuel can and drop some in the carb and glow plug. Let it sit for a few hours and away you go. I agree, do not take the engine apart. Fuel will loosen it up and then drain the fuel that you poured in and start it up. Good Luck, Dave

OK, thanks a lot. I will give it a try and report back to how it goes.

Do not soak in gasoline! the seals at the bottom of the carb and needle valve will be destroyed.

New orings at the carb and needle valve will probably be needed. You may need a new glow plug too.

Hi!
As it is a plain bearing engine ...just run it! Heat will losen up a gummed up trottle drum.
No new O-rings are needed!

Thanks for all the help. Let it soak in fuel overnight. Wiped it down and it turned over easy by hand. True test was today. I fired it up and she's seems to be running great.

Awesome!


CB

Success !

Yeah, LAs were designed for idiots like me. They start easily, run fine and last forever. There is nothing in them to go bad. Simplest engine in the world. Not a power house, but very reliable. Just a newer version of the old FP series, which had the same attributes.

Max, when Fun Fly events were still popular all I flew were Up-Roars and all they ever had on them were the .46 LA series engines. That was plenty of engine for the plane and I never had an LA that didn't start right up and run perfectly. The bushing engine does require fuels using Castor oil but about the only fuel I used on a regular basis was Power Master with the blended oil, still is my go to fuel. You are correct about them being idiot proof, I never hurt one but thank the maker they no longer make the .40. The .40 seems to be the engine of choice for every trainer I have been given and everyone of them has been worn out. They kept running though!!!;)

Yeah, Gene, the .40LA really does seem to be lacking in power, but the .46 is much better, really a bigger improvement than the slight increase in displacement would indicate, I have a .46LA on a Thunderbug and no matter how I neglect it, it still starts whenever I want it to and runs perfectly. There is a lot to be said for those little, simple engines.

Oh, another advantage is that since it is a bushed engine rather than a ball bearing engine, the crankcase is narrower. These puppies can be mounted in places too narrow for ball bearing engines.

Well as of today I have ran three full tanks through her and she runs just like a brand new one. Thinks for all the help. Just hard to believe how much I have forgot in five years.