Yamaha Overheating - Could Use Some Help

Discussion in 'Boats, Blinds, & Gadgets Forum' started by smashdn, Dec 4, 2020.

  1. smashdn

    smashdn Elite Refuge Member

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    Instead of rehashing it all over again here, I've included alink to another forum where i first posted my issue. Its a crappie website as i was using my side image unit when it first happened.

    https://www.crappie.com/crappie/mec...tic-2-stroke-oils-current-minor-engine-issue/

    Ive installed a thermostat where there was none. New water pump. New temp sensor. Pulled head and inspected. Flushed with ac

    iid
    sssolution.
     
  2. Phytoplankton

    Phytoplankton Elite Refuge Member

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    First thing I'd do is a full blown de-carb treatment, if that engine has been running cold (no thermostat for that many years) your gonna have serious carbon issues under the rings and the firing chamber (head). Carbon doesn't dissipate heat well. Sounds like everything else you did is spot on. You may have a minor obstruction in the cooling passages, those are hard to find. Also get rid of the oil injection system, mix your fuel, I know half adozen people who have fried engines from the oil injector failing. Might also rich up the carb just a bit. Good luck, let us know the outcome.
     
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  3. smashdn

    smashdn Elite Refuge Member

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    I really don't want to disconnect the oil injection. I know the risk is a catastrophic failure but dont want to deal with gummed carbs. It took me several years to get this motor sorted so I wasnt needing to rebuild carbs frequently.
     
  4. smashdn

    smashdn Elite Refuge Member

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    Do you think this is definitely awater issue or coukd it be oil? Cylinders are clean. I keep seafoam through it regular. I can spray some aerosol de carb in it though and help clear any residual carbon deposits.
     
  5. Aunt Betty

    Aunt Betty Elite Refuge Member Supporting Member

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    When it is in alarm mode have you felt the stream of water coming out the pee hole?
    Hot or cold?
    Warm?
    Could be false alarm. Id check the water temperature exiting to see.
     
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  6. darkvibe

    darkvibe Senior Refuge Member

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    I'm not a motor mechanic but have you considered a bad sensor and maybe it's not overheating even though it tells you it is?
     
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  7. Bullet21XD

    Bullet21XD Elite Refuge Member

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    It's almost always a water issue. If it's from lack of lubrication, it will just burn down. You're only notification will be...the motor seems to be running better than ever!
     
  8. smashdn

    smashdn Elite Refuge Member

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    The temp sensor is in the head between top and middle cylinder. It has been replaced. It is definitely the source of the alarm as i have disconnected the wires from sensor while alarming and tbe alarm ceases.there is no water temp sensor per se. The tell-tale water temp is not hot. When ra

    n in barrel it is same temp as barrel water. Verified with temp gun. Cylinder and water jacket temps are in that thread i linked to.
     
  9. smashdn

    smashdn Elite Refuge Member

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    IIf
    iit was ever in salt it did not appear to have any issues but it has not been in salt in the close to ten years i have owned.
     
  10. Phytoplankton

    Phytoplankton Elite Refuge Member

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    The fact that it was a problem before and after you replaced the impeller is troubling. If it only began to do it after the impeller was replaced I'd say you put the impeller in with the vanes pointing the wrong way, which can damage the impeller. Just a question, you mentioned gummed up carbs, do you run the motor out of gas before you put it up? If you choke it and get all the gas out of the carb bowls you shouldn't get gummed up carbs. I will still say, you're playing Russian Roulette with that auto oiler. I'm about to buy a Yamaha 2 stroke that had the oiler go bad under warranty and fry the powerhead. The engine was replaced under warranty, in the interim, the owner got another motor, but when he got this one back he disconnected the oiler and it's still got 5 more hours of double oil for break in of the new engine.
     

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