1977 Johnson 70hp

[Mntom]

Hi people, new (to this forum) guy.... I have a Johnson 70EL77 that started getting water in cylinder #3. Pulled it apart and found a gasket on the exhaust blown from the water side to the exhaust side in TWO places. My question is this: Anyone care to hazard a guess as to why it leaked? It never got hot to my knowledge.
Tom

 

[mrcj001]

Re: 1977 Johnson 70hp

Probably from its age........

 

[joey nathan]

Re: 1977 Johnson 70hp

33 year old equipment can, on occasion, wear out...

 

[jtexas]

Re: 1977 Johnson 70hp

It must have been a manufacturing defect.


nah.......I'm thinking it failed because of the intense pressure.


seriously though, I agree with the other guys, I don't know the design life of that part, but it must have been near the end.

but nevertheless, consider rebuilding the carbs & water pump just to be safe...it could be running at elevated temps, despite not having overheated. Test the thermostat, and might as well replace the poppet valves while you're in there. Test the overtemp circuit.

btw, welcome to iboats!

 

[Mntom]

Re: 1977 Johnson 70hp

Thanks guys. That was kind of what I was thinking, but I wanted to get a second opinion. Nothing I hate worse than trying to cheapen up a repair to only have to do it again..... (not that I have ever done that). Now to order the gaskets I need. The last head gasket job I did cost me about $600 (my diesel pickup). At least this one is way less expensive. Oh, I forgot... I just went through the carbs at the beginning of the season. I have only had it out three times since then.