overheated my motor

i have a 96 regal rush xp with a 120 mercury sport jet i overheated my motor and now i have water coming out of my lower carb so i pulled my plugs and i had water in my bottom two cylinders so i took the head of and looked at the pistons and sleeves everything looks fine do i need to just replace the head gasket or is there other things i need to look at thanks

Re: overheated my motor

Did you do this in or out of the water and if it was out of the water did you have a flush kit hooked up with the hose opened up all the way ??

Re: overheated my motor

i did it in the water,i ran it home with the flush kit and it was fine,so i took it to the water idled a little ways then went to take off and it cavitated and shut down opened hatch engine was overheated paddled back when i got home hooked flush kit back up and water started coming out of my lower carb pulled plugs and water in lower two cylinders

Re: overheated my motor

Common problem with the 120's , Replace the thermostat , pull the head check the head gasket , pull the exhaust manifold and you will probably find a blown gasket on it . This will allow water to build up in the lower cylinders . Head gasket is probably ok but better safe than sorry . The poor design of the exhaust manifold is the cause , no cure for it other than to use a OEM gasket that is thick , if you use a cheap low grade aftermarket gasket that is thin and waxy you will get to do this job again . While no one recommends sealer on the gasket I personally use SPRAY on Hi Tack from permatex , it is a red color and I spray each side of the gasket 3 times before installing . has worked well for me with no leaks. Do NOT use any kind of copper spray !! it will screw things up

Re: overheated my motor

im going to pull the exhaust off and check , i think your right my head gasket didnt look bad but thats all i could think of and how do i know if my engine is pumping water does it have a pee hole some where much thanks for the info lots of helpi know why my boat was cavitating i dont have a ride plate or grate on it at all will that cause motor to overheat and my serial number is rubbed of the fly wheel cover where else is it located and where is the jet pump number so i can order a new ride plate kit there are two of them so i need number thanks

Re: overheated my motor

Your engine number is located on the top of the block on a black and silver decal , if it is rubbed off you need to post up the wb numbers of the carbs (stamped on the mounting flange for the intake side) and this could give enough info to get the right ride plate number . You most likely did overheat due to no rideplate , water was not being directed into the cooling pickup for the engine.

The jet pump serial number is on the rear of the drive housing by the reverse gate cable mounting hole . Very hard to see if the drive is not out of the boat .