Head gasket or not ?

I am working on a freinds boat,he got stuck in the mud and "overheated it a little" now there is water coming out from around the head gasket and there is water on the plugs.It has been flushed and the water pump works.<br />The thermostat or temp sensor(rubber grommet with a wire coming out in the head)wire has the sheath melted off but it started right up ,ran and more or less idled.<br />Should I just start with the head gasket and see where it takes me or is it probly more serious than that.<br />1974 Evinrude 50 Horse 2 cylinder-Big gear case -Model #50473N-Serial #E002102<br />As I said it started right up(been sitting for 3 years) and ran fine,compression is not spectacular but o.k.<br />Thanks for any help<br />5150

Re: Head gasket or not ?

compression is not spectacular but o.k.

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What do you mean by ok ? ,are bout cylinder equal ?<br />If you are lucky it might rise some by replacing the head gasket .<br /><br />The first thing to do is to remove the head ,inspect the cylinders , maybe planing the head before replacing the head gasket .<br />If you are not so lucky you might have to replace the rings , and if you are very unlucky you might have to bore the cylinders .<br /><br />Inspect first , then come back to the forum to get more advice <br /><br />Replace the water pump , should be done every second year .

Re: Head gasket or not ?

When you take the heads off also drop the lower unit to replace the water pump and remove the cover for the tstats. Thennnn - backflush the motor by connecting a hose to the water pickup tube that goes into the top of the water pump.<br /><br />The sensor with the wire comming out of it on the head is for overheat warning horn. It needs to be tested (by grounding the brown wire) and probably should be replaced if the insulation is melted.