Johnson Cooling Blockage (picture)?

Sureshot

Petty Officer 3rd Class
Joined
Sep 28, 2011
Messages
97
Hey all, I have a J50PLSSM. With the head off I noticed what appears to be a blockage of one of the water passages. It's where the warm water flows out of the head on its way out of the motor. The other exit hole is clear. The engine ran fine with this apparently, no overheats and always had a good stream out of the tell tale. Anyway, any reason why this exit hole should be blocked or is this just some corrosion / etc. that needs to be dealt with. As always any advice appreciated.

H20 Blockage.jpg
 

orbanp

Petty Officer 1st Class
Joined
Jun 26, 2011
Messages
324
Re: Johnson Cooling Blockage (picture)?

Look at the mating part. Is there a matching hole to the blocked hole?
Have a look at the old gasket. Was there a hole in the gasket for that passage?
That should give you the answer!

Good luck, Peter
 

Sureshot

Petty Officer 3rd Class
Joined
Sep 28, 2011
Messages
97
Re: Johnson Cooling Blockage (picture)?

Yeah, definately should be 2 holes coming out of the head, through the gasket and into the power head. I'm assuming if left untreated this could eventually lead to an overheat?
 

phillnjack2

Ensign
Joined
Apr 30, 2011
Messages
918
Re: Johnson Cooling Blockage (picture)?

serios blockage !!!!!
just have a little prod at it and see what happens.
it definitely dont look right.
like said abive if the mating surface to this has 2 holes then just dig away at it.

This engine would also need a good run in nitric acid or saltaway to clean out the waterways for sure.


phill
 

jim j geezer

Petty Officer 2nd Class
Joined
May 16, 2012
Messages
189
Re: Johnson Cooling Blockage (picture)?

I'd be less concerned with that blocked port and MORE concerned about what appears to my eye to be a pair of fractures just outboard of and above those 2 threaded mounting studs. Use a magnifying glass if you must.
 

Sureshot

Petty Officer 3rd Class
Joined
Sep 28, 2011
Messages
97
Re: Johnson Cooling Blockage (picture)?

I think I'll try and drill or cut out whatever it is blocking the left hole. The pic makes it look like small cracks but it's just shadows. Another question, head gasket was put on last year so it's nearly brand new. Can I get by re-using it or does this require a replacement?
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Johnson Cooling Blockage (picture)?

I'd replace it................
 

Sureshot

Petty Officer 3rd Class
Joined
Sep 28, 2011
Messages
97
Re: Johnson Cooling Blockage (picture)?

Will do, thanks for the help.
 
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