Free a Stuck Engine

[Neverdone]

Just wondering what everyone's favorite method of freeing a stuck engine was. Recently got a sled from a guy that I KNOW ran 2 years ago, no issues. Then last year he pulled the cord and it is stuck. I pulled the engine and it is sitting on the bench and she is STUCK.

I dumped some tranny fluid down it last year when he told me about it cause I have seen that work before. Last night sitting on the bench it would not even think about turning. Last night I pumped it full of sea foam deep creep and am letting it sit.

Just wondered what anyone else favorite methods for that are??

[P [P [P

 

[EnglishBob]

Diesel in the block then a long handled socket weighted and left until it moves by itself.
But...I'm never in a rush.

 

[BigIrish]

I've read people have had a lot of success with a 50/50 mix of acetone and trans fluid.

Straight trans fluid is too thick to penetrate.

 

[sneakysnake]

If its stuck its going to have to be torn apart anyway. Tear it down, take a block of wood and a BFH and knock out the pistons that dont just push out.

 

[JBailey]

Brake fluid works pretty well also, but I like using diesel too. Just don't be in a hurry, it might come unstuck then you might get away with just a hone and re-ring it.

Marvel's mystery oil is supposed to work wonders on stuck engines too, just another option lol.

Is it a 2 stroke, if so I'd probably just knock the pistons out with a bfh since they tend to go bad anyhow.

 

[26Troadster]

marvel's mystery oil, or rislone.

 

[donsrods]

You can't rush the process, it took a long time for it to seize up and will take some time to free it up. I got a flathead that was frozen to move by putting PB Blaster down each cylinder and letting it soak, that didn't work so I removed both heads and put more in there and put a wooden block into the cylinders and hit it with a hammer to shock the pistons.

Kept doing that, while rocking the crank bolt back and forth slightly until it suddenly started to move slightly. A little more oil and more turning with the breaker bar on the crank and it freed up completely and turned all the way over.

Sometimes it is more than the pistons being frozen to the bores, it can also be the valve train, things like valves stuck in their guides.

Don

 

[Willowbilly3]

I bought a 294 Brut snowmobile for parts once. The engine was stuck so I poured Marvel Mystery down the plug holes and kind of forgot about it. A few months later I tried it, still stuck and I put in more MM. I might have done that three times over a year and a half. One day I checked and it turned. I cleaned the carbs and it started right up. I probably drove it 200 miles, it was a blast. It never would idle right, probably bad side seals.
We freed up a flatty once when I was a kid with ammonia.

 

[Old Iron]

50/50 mix of paint thinner and tranny fluid too.

 

[Neverdone]

Well Yesterday I pulled the jugs off the top of the pistons. Cylinders look pretty good, but the pull start side piston was the problem. Ring stuck in the piston, piston stuck to the cylinder. With the jugs off I poured some mystery oil in to the bottom end. It turns but seems a little tight so figure I will let it sit for a while, get some fresh gaskets, probably new pistons and a hone and throw it back together. Maybe bore it if need be.

 

[Neverdone]

Bottom turns freely now. Rings still stuck on the the one piston. Honed out the cylinders and they look perfect!!!

 

[8literbeater]

I had a shop teacher back in high school that showed us how to get a stuck cylinder off of a big old radial airplane engine that we had at the school. He'd soaked it and put air pressure in it and it still wouldn't move. Now keep in mind, the bore and stroke on this sucker is about 6 inches each. So he hooked up a fire extinguisher to the spark plug hole. I think he said they're charged to 250 psi. So anyway, he hit the lever, the cylinder shot past his face, over his shoulder, and put some hefty dents in the rafter of the shop. Problem solved.
He was a cool teacher.

 

[Neverdone]

sounds pretty dangerous................. BUT REALLY FUN!!!!