mercury mark 55 stuck pistion pic

[Britcheflee]

one stuck piston - afraid to whack on it too much - any suggestions how to persuade this guy to come out? the block is soaking in a mix of atf, diesel, gas and carb cleaner at the moment - what are your thoughts in putting a protected bit of pipe with the end cap back on the end of the rod and using that to tap down on?

 

[Chinewalker]

If you aren't set on saving the piston, you can push it out with a brass dowel from the other side, using a press. Take care to align the dowel good and straight as you don't want to bugger up the plug threads. I've also used hardwood dowels in a pinch. Not as durable, but less likely to muss up the piston or block.

I may have a spare standard bore piston if you need one...

 

[glenn property of pam]

measure a different piston to get a idea where the rings are compared to the ports. If the rings are at the same level as a port try to turn the piston either way to see if a ring is broken and jammed.