Hi guys.
Ive got a enya 40 2 stroke that is fitted in my trainer. This hasnt flown for a number of years and i thought it would be fun to get it in the air again.
My question is after giving it a test run on the ground the engine seamed to get hot quickly and hunt in RPM.
A friend of mine suggested that the engine might need cleaning internally because of lack of use. He said to soak the engine in MEK or similar solvent. Does this sound like a good idea?

I would do a search on antifreeze. There is a method of using Prestone to clean the engine.

I would also look at Carb Cleaner. Gunk sells a kit that you can use to dip your Holley carb in, and it works great with an RC engine. It is basically a 1 gallon paint can filled 2/3 with cleaner, and a basket. Give it a try, it worked well for me.

I am generally a enthusiastic supporter of the antifreeze method of engine cleaning, having cleaned 2 TT 46 Pros, an MDS40 and most recently an OS 40 FP. The 40 FP was painted with engine paint and even it came out bright and shinny!

However, A fellow club member tried the same thing on am older Enya engine he had, and it quickly turned dark gray! I don't know if there is something different in their metallurgy's, but he used the same Antifreeze I did (Prestone), didn't dilute it with tap water (Minerals in tap water can leach out and bond to metal), and used a ceramic lined crock pot, and used low heat. All the same as I did, but with a different engine.

If I haven't scared you yet, and you still want to try it on your Enya engine, start small. Try cleaning just the rear crankcase cover first. If that comes out OK, try the muffler. If that comes out OK, go for the rest. The only parts I didn't clean this way were the glow plugs and the carbs. I read somewhere that the anti-freeze destroys the platinum is the plug and not knowing what "soft" materials they use in the carbs I was afraid to clean them this way.

Just finished an Enya in crockpot. It also turned a mottled grey.

Think I would look in exhaust port & see what color the piston is , if brown or black I would tear it down & clean piston & sleeve with steel wool or Scotch -brite. Wash it out good with alcohol & put it back together & run it . Make sure the head is tight, that will sometimes give the troubles you have. MAX H

Do it just like max said but if you use steel wool I recommend you get "0000" or "000" from a hardware or furniture finishing store.

Right djlyon, forgot that. Also out here Scotch-Brite comes in three grits (colors) ,dark red (finest) , green (medium), & white (coarsest). All I ever use is the dark red. Some times the steel wool makes my fingers sore ! MAX H

Hi!
The only way to "clean" an engine internaly is to take it apart and inspect it!
The is two main things to look for: bad ballbearings and worn piston/liner.

If the engine has not been flown for several years and previously been run on castor oil fuel ...it definitely need new ballbearings!!
I have seen engines that turn quiet good but where the crankshaft just glided on the innerring of the ballbearing ......the balls being stuck from old castor oil varnish.
Also if the piston is brown /black with lots of carbon build-up from castor oil you have to either get a new piston /liner or clean the piston with fine steelwool (finest grade) or use 3M Scotch-brite pad finest grade. Most of the time if it's a ABC engine this cleaning-up process will take away some of the power the engine had compared to when it was new, but it will still run and throttle well.

Regards!
Jan K
Sweden

Poor needle and hot running? Definitely need to disassemble and inspect. Alot of engines I have seen do this ended up having a worn connecting rod. More often than not the exhaust has quite a bit of black residue in it also.

And my experience with Scotch Brite has green as the coarsest with dark red, grey, and then white being the finest. White is so fine it is just about unuseable. I use red and grey the most.