1957 Johnson 7.5 hp water problem

[riverrat 2]

I've been working on the gas tank for this motor. Finally got it rebuilt. Hooked it up to the motor today to see if it would fire. Started after about 10 pulls. I ordered an impeller but wanted to see if I could get it to fire or start first. The impeller is working good but I have water coming out the top cover housing between the housing and power head in the back. Any idea what this could be?I have the impeller kit do u think that some of those parts are needed to stop the leak or should I be looking somewhere else.

 

[ddwilson]

Re: 1957 Johnson 7.5 hp water problem

Look close at it when it is leaking and see if it could be coming from the bottom of the head gasket,
the other possibility is that the gasket under the power head is leaking and needs to be replaced.
Doug

 

[boobie]

Re: 1957 Johnson 7.5 hp water problem

That mtr may have a core plug on the very bottom of the cylinder head that may have fell out. Check that too.

 

[handifly]

Re: 1957 Johnson 7.5 hp water problem

A complete gasket kit is available at Outboard motor parts, Mercury, Johnson, Evinrude, new, used, NOS, classic, and vintage
I just bought one (no I don't work there
They also have a lower seal kit which is separate

 

[HighTrim]

Re: 1957 Johnson 7.5 hp water problem

If it is the base gasket, you will need to change that when you do the water pump anyways.

 

[F_R]

Re: 1957 Johnson 7.5 hp water problem

What boobie said. That motor has a core plug that is famous for rotting out. Easy to replace though. Just remove the lower cowl (pan) for access. Might as well replace all three while you are at it.

 

[F_R]

Re: 1957 Johnson 7.5 hp water problem

Part number was 27X309, now 306442