RCU Forums - How to loosen up a gummed engine

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How to loosen up a gummed engine

I am a bad person.

About 5 years ago, my club lost its field over the winter. I have 4 planes with .70-.91 FS engines. I did nothing to preserve the engines, and as things happen, I covered the planes with plastic sheets in the garage and stored them. Until yesterday.

Now we have a decent field, and the bug has bit me again. When I go to turn the prop on one of the planes, the engine is very gummy and stiff. I removed the plug and squirted in some WD-40, and turned it by hand until it loosened considerably. Then I got the electric starter and spun the engine. It is pretty loose, but is still stiffer than I think it should be.

Can someone give me some advice about this? I haven't filled the fuel tank, thinking maybe there's something else I should run through.

Thanks

Glow fuel. If you can spin it, start it up.

Thanks! That's pretty much what I had decided to do, but I was thinking there may be some other magic.

With the glow plug out flood it with fuel . Put a rag over the glow plug hole and spin it until it clears out. Then put the glow plug in and start it up.

I removed the plug and juiced it up with fuel. Replaced the plug, and, wow!--after 5 years started up like it never had an issue. Gotta get out tomorrow if I can gather all my stuff.
Thanks!

I'm in the same situation, getting old my engines loose, most of my carbs are in need of disassembly to get them going, also got the bug once more.

Quote:

Originally Posted by w4kv (Post 12684446)

First of all WD 40 is NOT a lubricant. Secondly you really don't know what had happened to the inside of your engine in the 5 years. If you have developed rusts in the bearings and/or the crank shaft which is made of steel squirting WD 40 in the engine and spinning it up with a starter will create a nice slurry of rust and WD40. If the slurry gets between the piston and the cylinder sleeve you have just created a nice bunch of scratches.

The proper way to resurrect an old engine is to take it apart and clean it. Then oil it properly with the correct lubricant and put the engine back together.