1979 Mercury 40hp 2 stroke cracked cylinder

[markwhitby45]

I have a 1979 mercury 40hp with a hole inside the rear water jacket on the cylinder block. I found water leaking around the sparkplug and was hoping a water jacket gasket would fix me up but then I was greeted by this lovely little hole :lol:

A couple pictures of the damage.
Photo Album - Imgur

I was wondering if there was any way to fix this without a new block. I assume a good welder could get in there and clean it up but wanted to get some advice on whether or not that would be a wasted effort. I also assume a complete breakdown and check of the pistons would be necessary but I've never gotten that deep into this motor before. Any assistance/advice would be greatly appreciated.

 

[Iceman66]

Re: 1979 Mercury 40hp 2 stroke cracked cylinder

You`re right, this could easy be welded by someone that knows what they are doing,using a weld-pin with the
right alloy.
After the welding ,you can do a compression test,that will tell something about condition of the piston and cylinder.

 

[oldman570]

Re: 1979 Mercury 40hp 2 stroke cracked cylinder

In your pic #1 it appears that the hole also is cracked up the plug and across the cylinder area of the piston. With the motor being a older module, it might be cheaper and better to try to find another motor of the same vintage with good compression, and use any parts off your motor to get it running good. This way you would have extra parts and could be cheaper and better in the long run. Otherwise it could be money spend on another anchor instead of a usable motor. JMO
Oldman570

 

[carholme]

Re: 1979 Mercury 40hp 2 stroke cracked cylinder

I agree with oldman and the cracking seems to come from something pushing through from the inside. Before I wasted any money on attempting a repair, I would split the engine as what you are going to find may well be beyond any repair.

Gerry