Maybe somebody can help me. I'm a former r/c builder--planes and boats. I'm selling a boat powered by a K&B 3.5 outboard engine. The engine is stuck. I tried a hairblower to heat free it up, but it didn't help. I'll have to deliver the boat in a few days.

Can anyone recommend a solution? The engine ran well 10 years ago and has been stored and covered since. It has a totoal of 5-10 minutes runningtime on it. Thanks.

Beeza

I think your talking about a glow engine, If so it most likely has old castor in it and sitting for 10 years I would say the caster from the fuel is rock solid inside the engine, Try soaking the engine in the fuel over night to soften it up and see if it will crank over, If it is a Ball bearing engine there may be rust in bearings also but they may be alright.

Dauntae

Put the engine in a 300 degree oven for about 10 minutes. The heat will soften the gummed up oil. Take it out and pour a little alcohol (denatured, isopropyl, etc) down the carb, glow plug hole, etc. Turn the crankshaft. Even if the crank only moves a little, keep working it back and forth. The alcohol will dissolve the gummed up oil. Keep pouring in additional alcohol and turning it over until the engine runs free and the alcohol comes out clean. Then put the engine back in the oven to evaporate the alcohol. Once the engine has cooled a bit, lube it with some after run oil.

Beeza,

I would remove the engine from the drive unit and check which is stuck. Did you ever lube the lower unit? Did you put it away with water in it?

The basic engine is a K&B 3.5 ABC schnuerle glow, if it's like mine. You might try some fuel to loosen it up. Also check that the carb is working freely.

Make sure you tell the person receiving it what you have done to free it. The person may want to take further steps like checking the bearings closely and checking that the wrist pin is not stuck to the conrod.

George

Hi!
The only thing that will loosen up old castor oil gum inside the engine is heat! Alcohol or acetone won't do!
Warm the engine ...either with a propane torch or heat the engine in the oven.
But! There is a but to this....The only thing that can't be fixed this way is the ballbearings!
They must be replaced by new ones if you are serious.
If you want to cheat...just let them be[:'(]


Regards!
Jan K

Agree heat is part of the solution. However, without a solvent, the engine will just stick again when it cools.
Oven is much safer, with a torch it's tough to evenly heat the engine.
Maybe, maybe not. It's quite common for them to be ok, just gummed up by castor. Since the outboards are often stored on the boat, which puts the bearings up in the air, they usually have not been sitting in fuel and any alcohol would have evaporated quickly. The remaining castor does a good job of protecting the bearings from moisture.

When I put one of my outboards back in service this summer, after it had been sitting in storage for about 20 years, I removed the engine from the lower unit and disassembled the lower unit and cleaned it out good. I also removed the back plate and carb from the engine so I could take a good look inside. Once I had cleaned out the engine with alcohol, it was obvious the bearings were fine, so I did not change them.

I've had luck in past using WD-40 and heat from heat gun. Once it moves a little, continue moving it and spraying more WD-40 in carb so it soaks through. You may have to take it apart to get at moving parts for lube.

Thanks guys! I used the oven---in 10 min the engine was free. didn't even stink up the house :-)
Excellent advice!!!!
Beeza

Great, except I didn't get a chance to wiz any wisdom before you fixed the problem! One of the miracles of castor is it's great rust prevention! I gave recovered engines run on all castor and set aside kept in a damp basement for 30+ years with no rust.

jess

jess

Great, now use some alcohol to flush the insides, and once it's evaporated, lube it up really well.