Pin hole in water jacket

pottydocpottydoc Posts: 2,176 Captain
 We have a large model 1980's-early '90's Yamaha 115 2 stroke on our flats skiff. Yesterday I discovered a hole about 1/16 in diameter in the water jacket behind the thermostat housing. Ant one had a similar problem? Will JB Weld fix it, or do we need to get it welded? It's located in the block, not in the cylinder head housing, it's not a bolt on piece. No I'd tag on the motor, so no further info on model, except it's a 20" shaft.

Replies

  • The Cat's EyeThe Cat's Eye Posts: 1,158 Officer

    I have heard of some people repairing small holes like that with JB Weld. Never have done one myself on an outboard. Don't forget to sand the area around the hole before applying the stuff.

     Many, many years ago i used JB Weld to glue in PVC pipes into the exhaust housing outlets on a I/O (350 ci V8) when the original outlets corroded beyond repair. The repair lasted for years and when the repair started to fail I just repeated it.

    JB Weld will probably last as long as a weld. LOL

    Giimoozaabi
  • surfmansurfman WC FLPosts: 4,228 Captain
    I would try it.
    Tight Lines, Steve
    My posts are my opinion only.
  • pottydocpottydoc Posts: 2,176 Captain
    That's basicly what I'm hearing on THT also. I'm gonna give it a shot. It can't hurt, and could save me some $$. The motor runs great, I'd hate to have to scrap it for a little bitty hole.





  • surfmansurfman WC FLPosts: 4,228 Captain
    edited June 4 #5
    The thing is that with that type of corrosion, the motor is doomed to fail anyway eventually. There is probably some accumulation of sand or something in the water jacket that has prevented the motor from flushing. I had an older Yamaha (1992 if I remember correctly) 4s 9.9 that really was poorly designed as far as the water jacket was concerned and it would accumulate sand in the head and there was real bad corrosion and pitting when I pulled the head. I tried repairing it but it didn't last too long.

    Hopefully your story will have a happier ending.
    Tight Lines, Steve
    My posts are my opinion only.
  • pottydocpottydoc Posts: 2,176 Captain
    I want a 90 anyway. They're just really hard to find used. This one is heavier than I really want on the transom, and, the boat is scary fast with it. It'll run better than 50 wot, and porposes badly while doing it.  Any faster than the hull is designed for (19' Jon boat.). So, I'll give this a try, and start on the 90 carbed Yam search again. I want to stay with the three cylinder motor to keep the weight down
  • Rich MRich M Posts: 1,010 Officer
    I used JB Weld on a hole like that in a Chevy block and it worked well - very well, truck is still running.  I say try the JB Weld.
  • pottydocpottydoc Posts: 2,176 Captain
    Actually, we found a used 70, looks great, no corrosion, no leaks, and good compression check. Traded the 115 to,the owner of the 70, plus a very reasonable amount of cash, for the 70. Plus he's gonna do the swap. The controls are the same for both. So, for not much money, we get about 75-80 lbs less on the transom, and a newer no corroding motor. The boat will probably still push 40, but it's got to be flat before you can run it that fast anyway, so we should be able to still cruise 30 pretty easy. Hopefully it will also cut out our porposing problem. If not, I'll move the starting batteries forward and see how that works. 
  • surfmansurfman WC FLPosts: 4,228 Captain
    Sweet.
    Tight Lines, Steve
    My posts are my opinion only.
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