78 Johnson 115 intake manifold

phx5kegsman

Petty Officer 2nd Class
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Apr 10, 2021
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Hello, I am rebuilding the carbs on my 115hp. After pulling both carbs and peeling off the gaskets, I noticed a "chip" in the intake manifold where the lower carb mates to it. See pic. Is this something that I should be concerned with?

TIA, Bryan
 

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Mc Tool

Lieutenant Junior Grade
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Aug 7, 2024
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Id make sure that manifold and the carb surfaces were flat, put a smear of gasket cement just around the chip (both sides of the gasket ) , bolt the carb up and leave it for a day .
You could dress it up and use liquid metal to fill the void and dress it up flat but its not a high stress joint ,and the carb has 4 studs holding it on , one of which is proximal .
Just make a good job of fitting the carb and I think it will be fine 😁.
 

Mc Tool

Lieutenant Junior Grade
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Aug 7, 2024
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Thanks. Any recommendations on Gasket compound?
Not from here 🙂 but Im thinking more mechanical strength than sealing . The gasket will do the sealing but just thinking about that gasket getting squeezed out where the support is a bit thin so ya wanna glue it in .
If I had to do it right now Id clean the metal surfaces with isopropyl alcohol (coz I got some )and a brush ,and then use threebond sealer , but any decent quality engine sealer will do ,permatex is good too
 

tphoyt

Commander
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Jun 10, 2010
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For what’s it worth that chip looks like a casting defect to me has has likely been there from the start. If it’s new I would be concerned about where the chip went but I don’t think the gasket sealing that area will be a problem.
Just my thoughts of course I could be way off.
 

Crosbyman

Admiral
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Nov 5, 2006
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6,040
Clean the surface of the chipped area with carb cleaner and just smooth it out with some JB high strength mix file smooth on the side and top and close it up.

the alternative is to leave it, close it, test it if it works don't fix it .
jmho
 

phx5kegsman

Petty Officer 2nd Class
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Apr 10, 2021
Messages
115
To Racerone's comment. I've changed just about every part on this motor: Complete ignition system (timer base, stator, power packs, coils, etc., starting, system charging system, fuel pump, cooling system, resealed lower unit. I have put way too much money into this "50 year old motor". But, I learned a lot and had the old girl running pretty good. The ONLY thing I have not done is rebuild the power head. I just figured on running it until it broke a ring and then rebuild it. A rebuild kit now costs over $900. I am sure that this old motor needs it, too. I'm just not sure what to do. On one hand: Since I have changed all of those parts and done all that work, I should complete the job and rebuild it. On the other hand, Is it really worth dumping another grand, or more into this old motor?
 

tphoyt

Commander
Joined
Jun 10, 2010
Messages
2,033
Sometimes I put to much money into the things I love. It makes no sense financially but it makes me happy so I do it anyway. I don’t plan on trying to make a buck on these things so it fine.
It’s much like cars that’s are toys you rarely get back what you put into them but it’s fun and you only live once.
 
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