91 Model P50 Head Gasket Replacement?

[kolortyme]

I am having trouble with my 91 Model P50 overheating after several minutes at WOT. It runs fine at 3/4 and half but when it is a WOT the alarm goes off and it runs poorly until it sits a few minutes at idle. There is also a small puff of white smoke (steam?) when it is cooling off. I recently replaced the Impeller and I'm getting good flow through the pee hole. From other comments on this board it sounds like it could be a leaking head gasket. How much does a typical head gasket job cost for an expert to repair? How many hours would it take me to replace? I'm a novice mechanic but can usually mutter through moderate mechanical tasks.<br /><br />Thanks for all the great advice.<br /><br />Will

 

[ianyoung77]

Re: 91 Model P50 Head Gasket Replacement?

Have you checked your thermostat? Both this and the thermoswitch can be easily checked. When you pull out the thermostat have a look at the chamber to see what the water system is like.<br /><br />Generally a head gasket can be checked using a compression tester. If it does need doing it should only be a few hundred, however, gaskets almost never go without head warpage. This will need machining/sanding but this usually included in the price. If the head is cracked then you can double the price.

 

[kolortyme]

Re: 91 Model P50 Head Gasket Replacement?

I pulled the thermostat, cleaned it, and checked to see that it was opening in water on the stove. It seemed to be working fine and I am getting a strong stream through the pee hole. If it is only a couple of hundred to have the head gasket replaced I'm assuming it's only a 2-3 hour job? Since it runs good at less than WOT it seems like the head wouldn't be cracked.

 

[rodbolt]

Re: 91 Model P50 Head Gasket Replacement?

2-3 hours unless a head bolt or water cover bolt breaks. add about an hour or so for each. unless its one of the lower head bolts then all bets are off.if the bolts dont break that is a easy one to repair. make sure the head is checked for warpage once cleaned. cleaning the gaskets and surfaces is the hard part.

 

[easygo0]

Re: 91 Model P50 Head Gasket Replacement?

Will is boat new is it rigged right motor might be sitting to high on transom for intake at WOT

 

[kolortyme]

Re: 91 Model P50 Head Gasket Replacement?

I pulled the head and exhaust covers with out any major problems. There was a lot of buildup on all parts. Is there a trick to getting off all these deposits and the old head gasket material? Someone said drano worked well. Should I take the head to a machine shop or do most marine mechanics normally service the heads themself?<br /><br />Easy, this is a used boat I purchased recently. The water intake grate is about 2-3 inches below the bottom of the boat. Is that low enough? What should it be? It looks like the motor is set as low as it can be without a different mount. <br /><br />thanks for all the advice!