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Help! Help with 2 stroke

#1
So for my birthday my dad bought me a very old kyosho cessna skyhawk.I like working and repairing planes as much as flying.
The plane has a small 0.5,2 stroke engine, what I believe.(New to gas related stuff)
Took apart the spinner and all its components until I got to the shaft. I cant check on the piston housing or the head because a screw broken and cant get it out.I
havent checked the exhaust.


-THE PROBLEM: I cant freely spin the engine, it is stuck (dont know where)It is impossible to turn.

Any helps or ideas to fix it?
 

Bricks

Well-known member
#2
Is it gasoline or a Nitro engine if it is nitro the castor oil will get very stiff when it has sat. You can take a heat gun hair dryer and heat it up and slowly work the engine back and forth until it frees up. Once free put some 3-1 oil gun oil or some type of light lubricant to keep it from freezing up again. If it is gasoline motor you may have more issues and need to be torn down to find the problem.
 
#4
also pull the glow plug if you can and put 3 n1 down there as well, try turning it over without the plug as well that was compression wont fight you.
 

L Edge

Active member
#5
If the piston doesn't budge, get some mystery oil, pour in above and below piston and surrounding housing and let it sit for 2-3 days. Then try to free it up. Chances are the bearings are shot if it has been sitting around for a long time as well. 2 cycle engine always absorb water and do the damage.
 

PsyBorg

Wake up! Time to fly!
Mentor
#7
Pb blaster will free nearly anything.

As for the motor they are usually brass sleeves inside the aluminum jug. The tops are tighter in yolerence to produce compression while the lower sleeve is a tad loose so it can pull fuel up out of the low end.

Pb blast should free things up. If you want to speed the process take a heat gun or a hair dryer and warm up the top part of the jug. Then work the shaft back and forth to start breaking things loose.

You could also flood the crank case with transmission fluid. Thats basically all after run oil is.
Let that sit for a week n work its way into things.
 
#9
Chances are the bearings are shot if it has been sitting around for a long time as well. 2 cycle engine always absorb water and do the damage.

I'd be more inclined to blame castor schmoo than rust, unless the PO ran their engines hard and put 'em up with fuel in the crankcase. I run mine until they stall due to fuel starvation and don't have rusting issues even long-term...and I don't even use any sort of after-run treatment beyond setting the piston down in the lower half of its stroke.