Johnson 25hp water lower cyl
 

hi guys i have an old 25hp that when u idle idle in the water the lower cylinder miss fires . its getting water in it. could the head be the cause of it or the lower crank shaft seal .if it was the lower seal wouldnt it afect both cylinders. want to save doing extra work to fix the old girl .also want to use her for a aux when i test run my boat

Look at the head gasket.
I had two that leaked there.
If it's not obvious, look for a different color somewhere around the metal portion of the gasket and check the head or block for a pit in that location.

I would also check the head gasket.

X3...What Tsubaki and TheFermanator just said.. Head gasket... and to narrow it down even further, check the lower part of the gasket, since that's the cylinder that's getting water in it. :beer:

ok then it could be the head or gasket no chance of it being the lower seal ill get the head off thanks

I've seen Yamaha's corrode thru the lower water jacket in the head, they would check good on a compression test, but when I ran it, it would miss, finally got bad enough when I was spinning the engine over with the plugs out, it would spit water out of the plug hole. From what I've seen on Johnson, I'd do what every one else suggested and check the head gasket