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Looking to buy used is 98 yamaha gp 800 93hrs. limited,the other is95 seadoo gts580cc 177hrs.what should the compression test reading be and what else should i check?

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For a motor to run the compression needs to be over 110 PSI. The normal compression will be between 130 PSI and 175 PSI . What is important is that both or all three cylinders be with in 5 to 10 PSI of each other. If one cylinder has much lower compression than another it is an indication that motor work is necessary to fix the imbalance. With older boats it is always a good idea to pull the motors and replace the crankshaft end seals. Also it is not a boat if it does not float. Inspect the hull for damage, cracks , holes, bashes/bruises, these will need to be repaired. Figure out how to look into the intake grate and inspect the impeller and mated surface for nicks damage. Seadoo's have a replaceable plastic ring around the impeller ($80) that is easily torn up by rocks and debris. If the gap between the impeller and the ring is wide you will lose significant thrust. Only your own sweat equity will make a boat needing a lot of work a good deal. Happy Riding.

Posted on Jul 07, 2011


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