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Thread: overheated 780

  1. #1

    overheated 780

    so i took my 97 780 out today for the first time this year. I made it a ways and relized somthing wasent right. then inside flooded, i floated back to the ramp took off the seat and the motor was under water and boiling hot. I found the hose on the coolant rail pop off. by this time it was hot. let it cool check compression removed cylinder head and it looks good no scoring or what not but it was full of water. my question is what filled the cylinder with water. head gaskets water in carbs. what should be my next step.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    There was water INSIDE the engine, or just in the hull?

    You 'floated back to the ramp.' Was the engine still running while the hull continued to fill with water?

  3. #3
    no it was only filling up the hull running but when i pulled the cyl heads the pistons had water around them im thinking head gasket becouse head isent really blue anymore it go pretty hot

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    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by jdogg View Post
    no it was only filling up the hull running but when i pulled the cyl heads the pistons had water around them im thinking head gasket because head isn't really blue anymore it go pretty hot
    Did the water drip in from the water jacket when you opened up the engine?

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    Connecticut CrazyA's Avatar
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    Quote Originally Posted by jdogg View Post
    so i took my 97 780 out today for the first time this year. I made it a ways and relized somthing wasent right. then inside flooded, i floated back to the ramp took off the seat and the motor was under water and boiling hot. I found the hose on the coolant rail pop off. by this time it was hot. let it cool check compression removed cylinder head and it looks good no scoring or what not but it was full of water. my question is what filled the cylinder with water. head gaskets water in carbs. what should be my next step.
    I'm a little confused. If the motor was completely under water, how did you "float" anywhere? With that much water in the hull, the ski should have been barely afloat, let alone manuverable by floating. Also, if it was under water, how was it "boiling hot" ?
    Also, the waterline from the waterbar is the water exit, so if that's the only line that was off and leaking, then water was making it through your motor making the overheat situation even more suspect???
    If the motor was "under" water, it got in everywhere. Through the carbs and exhaust system.

    Slow down and walk us through it step by step, and don't leave anything out.


  6. #6
    ok i was like 15 feet from the ramp and jump off and pushed it to the ramp it was almost a gonner. as for the motor the tops of the cylinder where just barly out of the water they are almost black now. and yes i found the hose from the water off thats what filled up the ski does it sound like i have another issue for the over heat

    ---------- Post added at 05:02 PM ---------- Previous post was at 05:00 PM ----------

    and the water leaked in from the holes around the piston i guessing that wasent normal

  7. #7
    Connecticut CrazyA's Avatar
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    It sounds like you're maybe talking about water coming through your cylinder ports. No, that's not normal, but in this case it makes perfect sense if you left the crankcase filled and then pulled the heads and turned the motor over. The pistons down stroke would force the water up your transfers and out the ports. For now you need to get the water completely out and get everything completely lubed up. PRONTO

  8. #8
    yeah that is what i did so hopfully ill fix the water leak and replace some gaskets and it will be ok

  9. #9
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by jdogg View Post
    ... hopefully I'll fix the water leak and replace some gaskets and it will be ok
    Just to be clear - you need to get the water out of the engine, and get it running, right away. Even 24 hours with water sitting in the engine might be too long.

    The idea is to get the water out quickly, before the steel bearings inside the engine begin to rust. Even a little rust in the bearings is too much.

    Once you get it running, the heat will help dry out the engine internally. Once the engine is dry inside, you then spray fogging oil down the carb intakes to protect the engine from rusting. Only THEN you can relax.

    You can search for more tips on recovering from a flooded engine.

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