Best Way to Unseize an Engine

[pj43]

I have a seized Johnson from the 50s and was wondering what the best product or method was for unseizing an outboard. I am not sure how the engine got seized, but I believe it is from long periods of inactivity. Any help would be greatly appreciated.

[b-morrison]

it can be as simple as BP blaster in the cylinders and wait or 1/2 transmission fluid and 1/2 lacquer thinner and soak, test, soak. Then there is applying heat to the cylinders and tapping the pistons thru the spark holes if possible. Remember do not apply flame/heat to motors with fumes and gas/thimmers etc. Time and patience and a bit of luck…..

[legendre]

If it’s really seized hard, as in the rings / piston are essentially welded to the cylinder walls, then you’ve got a real mess on your hands..

If it’s only sticky-stuck from sitting, where a little rust forms between the rings and cylinder walls, then you can get it moving just as B.Morrison suggests. Use penetrant, heat, tapping, time and patience. If it is stubborn, remove the cylinder head for better access to tap and/or apply penetrant.

[dave-bernard]

If the ports are covered by the piston you can make a tool from a sparkplug and zerk fitting and use a grease gu to use hydrolic pressure. but be carefull.

[jcrigan]

First, check to make sure it’s the powerhead and not the lower unit. On the powerhead, also put penetrating oil i nto the crankcase to free up the crankshaft if that is what’s stuck. It will get to the bottom of the cylinders and help that too.

[legendre]

quote Dave Bernard:

If the ports are covered by the piston you can make a tool from a sparkplug and zerk fitting and use a grease gu to use hydrolic pressure. but be carefull.

This is a new one, to me.. wow, that’s quite a technique!

[david-bartlett]

I remember reading a post Lloyd made, where he recommended pouring hot water over the block. This caused expansion over a larger area, which then allowed things to move a bit.

Worth a try.

[Buccaneer]

Would electrolisys work? Would it mess up an aluminum block?

Prepare to be boarded!

[chinewalker]

Complete teardown is the best way to repair it as then you can deal with any rust ridges in the bores, crusty bearings, pitted crankshaft, etc. You can punch the pistons out with a press, using a piece of metal dowel on the rods to avoid damaging them. You might get lucky and find you can tap the pistons out with a wooden dowel using any of the penetrating elixirs mentioned above, but if they’re really stuck, save your time and frustration and just punch them out with the press. Other methods may be needed on blind bore motors, but I have done dozens of OMCs this way and it works very well with them.

[crosbyman]

https://www.youtube.com/watch?v=Q-Gq8i73gYs

timely video for my 9622a stuck beauty 🙂

Joining AOMCI has priviledges 🙂

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