[JohnNC]

The motor sat for many years without proper storage or useage. The powerhead is seized. I have applied oil to the two cylinders and will allow them to sit for awhile prior to attempting manual rotation. If I can't coax this engine to rotate, what are my options?

[NathanY]

Have you tried penetrating oil? That usually works. Sometime I do this ( I am not saying it the right way or the best way, just what I do sometimes) I take the head off and use a soft piece (pine) of 2X2 and gently tap the the center of the piston, after it has been soaking for a while. If you hit it hard you will do severe damage. I use soft wood so that if I do graze the cylinder wall it does not scratch. Remember gentle is the key. Do not get in a hurry. Like I said this technique might not be your cup of tea, there are other way to do it and maybe better ways to do it. This is just the way that I do it on MY OWN motors.

[Bobby D.]

Hi John, I have successfully freed a seized small outboard the same way that Nathan suggested.I used diesel fuel in the cylinders and alternated hitting both pistons.When you get it freed check for frozen piston rings and scoring on the cylinder walls. If you don't know how to check for frozen rings; try this: when the pistons are free bring each cylinder up to the top of the cylinder and with your finger tips move the pistons side to side not up or down. Cylinder scoring is checked by using your fingernail. If your nail gets caught in the groove (not a good thing).

[alcan]

Hi John Sorry, You won't be able to remove the head on your little Merc. They are constructed differntly. What looks like a head is just a water jacket cover. You might, how ever, be able to tap the tops of the pistons with a wooden dowel thru the spark plug hole. Be careful, The piston won't put up with much of this. It is easy to punch a hole in the top of the piston doing this. I would remove the exhaust cover plate, This will expose the exhaust ports and allow you to see inside somewhat. Also remove intake bypass covers, this will let you in the other side. You will also be able to get your solvent in there better. I feel that a strap wrench on the flywheel is better than pounding on pistons. But under these conditions you gotta do what you gotta do. If the motor dose come free test for stuck rings by poking them with an awl thru the ports. They will be springy if OK.