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Thread: Looking for some advice. Motor heating up

  1. #1

    Default Looking for some advice. Motor heating up

    I have a 22' seasport with a volvo 302 fuel injected motor. Last year one of the heat exchangers plugged with scale and heated the manifold to where it cracked and the rubber couplers to where they were quite crispy. I have replaced the manifolds and heat exchangers with new ones and the right side (from the back) heated up much more than the left side. You can see much more water coming out of the left side. The right side looks more like a heavy mist compared with actual water coming out of the good side. I replaced the impeller in the water pump but have yet to run it to see if this helped. The temperatures with a laser temp gauge is the left side is at 73 degrees and the right side around 130 degrees. My next move is to check the water outlet at the transom to see if this might be restricted possibly because of the scale that initially caused the failure.
    Any thoughts or if anybody has experienced this would be greatly appreciated.

  2. #2
    Member FishKing's Avatar
    Join Date
    Feb 2009
    Wasilla, Alaska, United States


    compression check. I had the same problems in a jeep and did a compression check and found a burnt valve from over heating. Also. check all the water ports again................ Good luck

  3. #3

    Question Risers???

    Mine did the same thing. You didn't mention that you replaced the risers or not. The risers are usually the culprit, they plug up with rust and scale then cook the boots. If you didn't replace them...

  4. #4


    It was the risers not the heat exchanger that was replaced, sorry.

  5. #5
    Member Soundfisher's Avatar
    Join Date
    May 2006


    Quote Originally Posted by FishKing View Post
    compression check. I had the same problems in a jeep and did a compression check and found a burnt valve from over heating. Also. check all the water ports again................ Good luck
    I would follow this advice, and would make sure that the manifolds and the risers are replaced. MANY engines are ruined by trying to get to much time out of them. It causes the head to heat up and burns/tulips the valve. Also it is common for them to leak after the engine is shut down, causing water to leak into your exhaust port then your cylinder.

  6. #6
    Member .338WM's Avatar
    Join Date
    Jan 2010
    Eagle River


    If the heat exchanger got so hot as to cook the rubber the head gasket/s are likely toast. If you can run it on the trailer, pull the cap off the cooling system and fire it up, watch for bubbles and coolant pushing out the fill hole. Also check for an odor of exhaust in the coolant. Another indicator of a head gasket failure is moisture on the spark plug or steam exiting the cylinder after running the engine then removing the spark plug from the suspected cylinder/s at fault. Pull the dipstick from the crank case and check for a normal/abnormal(overfill) level and signs of water contamination ( milky appearance ).

    There may be a valve problem as mentioned but, that will not cause what you describe with the seeming lack of water out the exhaust, a cracked riser/manifold, or riser to manifold gasket will allow water to enter a cylinder by way of exhaust valve. If that is the case it would likely be evident when starting the engine either by a misfire, and/or hydro-locking of a cylinder ( hard/drag cranking ), which could lead to a bent connecting rod.
    Failures like this are often more severe than first realized due to a cascade effect from the original culprit to everything down the line.

    Be sure to double check all of the water supply and return ports/fittings for restrictions, if scale was a problem there is a possibility that there is scale in other places, and some may have come loose to cause an issue someplace else in the system.
    The difference between genius and stupidity is that genius has its limits.

    Albert Einstein


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