I've had this .40 stored after some uses over the years and now want to get it out and put it to use. The problem is that the piston is a little gummy/hard to turn. Is there anything I can add to the fuel or piston to clean it out? Different % of fuel, like 20 or even nitro?
Thanks Ryan

Thinner!

It is probably castor gumk. Soak it in fresh fuel for a day or so & it should free up nicely.

What britbrat said. I just did that with an engine that was almost stuck and the results were amazing.

Serafim

Go buy yourself a $10 - $15 Crock-Pot and and some Antifreeze and soak the engine in the antifreeze in the pot overnight on low heat.

Remove and rinse with clean fuel and it should be as good as new.

You may want to remove the Carburetor and just let it sit in some fuel overnight instead of putting it in the crock-pot.

Please do this in the garage or outside in a shed away from your living quarters.

.....and don't re-use the crockpot for food!!!

Just fill it with Marvel Mystery oil, and turn it slowly, after about 1 minute, it will start turning smoother and smoother. 5 minutes and its turning as if it were new.

I'm sure just dumping it in some clean fuel for an hour will sort it...

I bet you if you remove the Glow Plug... Pour fuel into the top and into the carb... Shake well, flip the prop 20 times... empty, add new glow plug, and prime it will fire no worries...

Matt