Force 40 low compression

Hey again everyone! I recently posted about a Force 40 that wouldn't start and it ended up being the head gasket.... well I put a new head gasket on and it ran fine for a few months... the other day it started acting up again
.. it will start of you have the idle up but it shuts off as soon as thearly idle goes down... I did a compression test and the upper cylinder has 145 psi and do the lower has 40 psi... I haven't taken it apart yet but assuming it's the head gasket, why would the head gasket go so quickly? Incorrect installation? Defect in the head gasket? Anyone have any clue why it would do this? Thanks again in advance!

The problem could be any that you listed???????

Pull the head and check for damage?
Since the gaskets fairly new, you can probably reuse it with a little silicone.

Well I took the head off and the lower piston is done. About 1/4 of the piston head is pushed out(like it's warped) Any idea what could have caused this? And how hard would it be to replace the pistons on this? I've never dug that deep into an outboard before.

If you can rebuild a carb?
And if you have a 1/4" 12 point socket, you can do it
BUT!!! you need a factory manual for the right specifications.

ANY damage to the cyl. walls?
Post some close up pics.

Usually ANY scoring means a .020 over bore job.

Keep us posted.