very frozen piston

[rolmops]

This is a 1993 9.9 johnson.My b.i.l. last used it in 1999 in the ocean and had to stop the engine because it started "schreeching".It did not actually set up but it did not move afterwards.Having taken the powerhead apart,I managed to get the upper piston out.It had a bit of rust on the sleeve,but magic mystery oil penetrated and loosened it up.The #2 is another story altogether.4 days of penetrating oil does nothing,hammering on the piston in either direction does nothing.People tell me to use coca cola instead of penetrating oil,others advise antifreeze .I am considering to use a press but it may take the sleeve out.<br />I don't know what to do.What should I do??<br />Thanks for any suggestions.

 

[R.Johnson]

Re: very frozen piston

Won't a hardwood block, and a hammer move it?

 

[British Seagull]

Re: very frozen piston

Mate realy that motor is buggered your better off finding another as the cylinders could be badly scored and once their gone its not worth fixing unless you have the right skills and tools. but have you tried applying heat to the cylinder as well as oil as that can often loosen it up?

 

[Dave Abrahamson]

Re: very frozen piston

You need a bigger hammer... and plenty of patience. It'll come out eventually.<br />Good luck!<br /><br />Dave

 

[Silvertip]

Re: very frozen piston

kWhat you don't need is a bigger hammer or a press ---- just yet that is. What you need is patience. With the piston facing upward, load that cylinder with pentrating oil. Tri-Flow works well on rust. Let it sit. If the oil drains away load it again but don't try moving the piston. After a week or so, gently "tap" the piston with a hardwood block covering as much of the piston crown as possible. If it moves even a slight bit -- move it the opposite way a bit (assuming you can get at it from below). Load the cylinder again and let it sit. Once you get a slight bit of movement, the trick is to keep moving the piston within those limits. It will move a tad bit further each try until its finally free. As others have suggested, the sleeve and piston are likely damaged and as a minimum will require boring and a new piston.

 

[surlyjoe]

Re: very frozen piston

put the block in teh oven and warm it up to operating temp, then spray some air blaster upside down, so the liquid comes out into the bottom of the piston it should shrink it enough to break the weld and beat it out the end. we used to use this trick to get seized VW pistons out of the barrels so we could reuse them

 

[rolmops]

Re: very frozen piston

Thank you guys for your input.I took the step and put it under the press.piece of cake.no damage on the walls and all it needs is a bit of cleaning up and polishing.