Hey guys. I just recently got back into the sport and pulled my os fs-70s out of the shed. It was out there for about 9 years with no rust protection oil in it. I took the valve cover and rear crank cover off. Intake valve was stuck open and there was rust on the crank and rear bearing. I soaked it in wd-40 for a day and got everything loosened up. The engine turns over very smooth and has good compression. Now I'm worried about the rust. The actual balls in the bearing look like new and I dont hear any unusual noise when I turn it over. What should I do? Thanks.

Flush it out good. Feel carefully for roughness in the bearings.

If OK, then put it in the air. But keep an eye on the bearings.

Enjoy,

Jim

Since you say it's nice and smooth...you could probably just run it, but....

The rear bearing on the .70 is a common bearing, that is easy to get from just about any industrial parts supplier. You can get a top quality part for around $10. If you're so inclined...just replace it.

If you'd like the specs on the bearing...I'll try and dig one out.

'Race

**EDIT**

The part is an NTN 16002 bearing (or SKF equiv). Dimensions are: OD: 31mm, ID: 11mm, Width: 7mm.

Don't waste money on shielded/sealed bearings. A plain, open face bearing is ideal for this application.

I just bought two bearings at my local bearing house for my OS H-80, $11.37 for the big one and $3.68 for the little one. All Class three bearings just like the ones that came out of it. You might want to price some new ones just for kicks and see if the cost of replacement is worth your peace of mind.
Just my opinion

keep us posted i think she will purr like a kitten

Well I flushed it really good with wd-40. Looks pretty clean now I think I'll give it a try. Its going into a aircore colt till I get my feet wet again then I was thinking about a 4 star. It only probably has 4 or 5 hours runtime on it. Now I just need to get my old futuba conquest up and running. Thanx alot for your help guys.

One more question. What is a good fuel to run in this engine I cant remember what I used to use.

THIS IS FROM THE TOWER SITE for your engine: Fuel: 10%-20% nitromethane with 18% lubricant. Synthetic, castor, or a synthetic/castor lubricant blend may be used.

Any good fuel will do such as Wildcat Fuels, Mogan Fuels (Cool Power or Omega), Byron Fuels, and S&W Fuels. Just follow the guidelines of what the manufacturer says above and just about anyone of these fuels will work just fine for you. I would probably go with 15% Nitro as I think it is the most commonly used. I hope this helps.

If you are concerned about the rust you might want to bench run the engine for a tank of fuel. Usually the rust is superficial and does not pit the bearing.

Bill

cool power all the way 15% nitro if you need any more uh go higher in nitro count