I had an old control line plane given to me and it had a fox 35 40th anniversary engine on it. When I got it I couldn't get the propeller to turn at all. I took the head and back plate off along with the propeller and soaked it in kerosene for a couple of days. It turns over now but it seems a little stiff. However, I really have no reference to what stiff is so I don't know if it's still gummed up or if it just has good compression. How can I tell if this engine is worth buying fuel for and spending the time to get it going?

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it sounds like it needs to be cleaned better, it's the Castor Oil that has hardened, you could wash it out very-very good with hot-hot water (the heat will melt the Castor), then rise with rubbing alcohol to get the water out, then once dry re oil, or better yet soak in Antifreeze in a crock pot for 5 or 6 hours, the Antifreeze will clean it, then rinse well with rubbing alcohol, dry well and re oil,,, then see if it turns over smoother

Jim

Just soak it in acetone for 10 minutes. Empty, rinse, let dry, oil the dickens out of it. Fuel it up and run it. Don't mess with petroleum solvents or water. They won't be nearly as much help as acetone or even some glow fuel. Acetone is superior for dissolving organic oils.

thanks for the tip, I haven't heard of it, it sounds like the simpler way to go

Jim

What do I oil it with after rinsing in acetone?

rinse it first with rubbing alcohol let it dry,,

if it is going to set for a year or 2 use ATF..

you can use ATF if you are going to start it in a couple weeks or months, but make sure you rinse the engine well with fuel before you start it to get the ATF out

Jim

Just soak in acetone for while. Dump it out. Flush with clean acetone, dump it out. Let dry well inside as-is, then oil it with whatever you have. ATF, air tool oil, 3-in-1 oil, sewing machine oil, etc. Lubricate liberally. When ready to run it, just prime it like any other engine and run it. Once running, it will blow whatever oil out that is in it. Most oils aren't compatible with methanol, so rinsing it out with any kind of alcohol isn't going to do much good.

So here is an update......I let the engine soak in acetone for about 20 minutes. When I got it out, I could turn in over with my hand on the crankshaft. I made sure all the acetone was dried out and then I got a little oil on my finger and wiped it over everything I could reach. While I was putting everything back together, I noticed that at the top of the stroke there was a little bit of of play before the crankshaft engaged the con rod again. This may be normal as the motor turns but it did not seem as fluid of a movement as I thought it would. Anyway I put everything back together and tried turning it over again. It turns over just fine but as i try to spin the propeller with a rod it doesnt act like I thought it would. I thought it would give me a little more flipping action than it does. I put a link to a video for yall to watch to see what I am describing. The problem is I really dont know what to expect because I have zero experience and no one around me knows anything about these engines either. So what do yall think? Is this motor worth moving forward with?

Video link: https://www.youtube.com/watch?v=6ZN4...ature=youtu.be

It probably needs some fuel in it to loosen up a little more. Prime it up and fire it up - it's probably fine.