96 75hp water in two bottum cylinders

[jeffrey3812]

I was running down river boat started to chug and died no alarms signaled didn't want to start finally got running made it to marina would not run full power. Took out plugs there was water in the bottum two spark plugs changed head gasket still did not run right or idle. Took to shop they could not see anything wrong, charged me 160$ for nothing. Took back apart could not find any evidence of a cracked block any suggestions.

 

[pnwboat]

Re: 96 75hp water in two bottum cylinders

It could be the exhaust cover gasket (#16 in diag. below) or the stainless steel exhaust plate (#17).

http://www.boats.net/parts/search/Merc2/Force/75%20H.P.%20%281996%29/0E138600%20THRU%200E202999/CYLINDER%20BLOCK%20ASSEMBLY%20%28SERIAL%20%23%200E181483%20THRU%200E287999%29/parts.html

 

[ejbalboa]

Re: 96 75hp water in two bottum cylinders

hi fellas the force engines have a bottom cover whitch is lower part of the block water inlet port is part of that casting that cover covers the exhaust port and also the cylynder area of water flow.
There is a 1/4 inch of wall that seperates the two and there is no gasket only case glue or silicone when that is corroded enough the water fills the bottom cylinders when sitting or low idle.

 

[Mark9740]

Re: 96 75hp water in two bottum cylinders

hi fellas the force engines have a bottom cover whitch is lower part of the block water inlet port is part of that casting that cover covers the exhaust port and also the cylynder area of water flow.
There is a 1/4 inch of wall that seperates the two and there is no gasket only case glue or silicone when that is corroded enough the water fills the bottom cylinders when sitting or low idle.

ejbalboa,
I don't quite follow you. I am having a similar problem with my 85HP Force. How can I access that area/gap that needs to be sealed to prevent the water from leaking in? Do I have to go through the head?

 

[pnwboat]

Re: 96 75hp water in two bottum cylinders

ejbalboa - not exactly sure what area of the block you are referring to, but it sounds like you are referring to the spacer plate that is bolted on to the bottom of the block? There is supposed to be a gasket between the block and the spacer plate. Refer to the diagram I posted above (Item #21). To replace it, you have to remove the power head from the lower leg. I'm no expert, but I've seen many exhaust cover gaskets fail and let water into the lower cylinders. Also sometimes the stainless steel exhaust plate develops a crack and does the same thing.