Force 1988 50hp Overheating

[billyjake33]

Had a previous problem with compression of top cylinder. Pulled head found it was the head gasket. Replaced that ran perfect first two time times out.<br /><br />Noticed that some of the paint appeard to be bubbleing up on the head. When running at idle water sprays pretty good out of the two holes but when running fast it seems to be mostly steam and exhaust.<br /><br />Replaced the impeller last year redid all of the lowerunit seals and impeller looked fine this year.<br /><br />After noticing the bubbleing of paint we removed the thermostat and left it out.<br /><br />Well this trip we ran fast for about 2 miles or so then the motor dropped to half speed and then nothing (exactly what it did when head gasket went previously) Took the cowel off and touched the head got burned instantly. Put some water on it and it boiled right off.<br /><br />Trolling motor got us back in. When we got home pulled the head off and top cylinder wall was visibly scored. Not real bad but can feel it with my finger.<br /><br />I'm holding back the temptation of taking the 12 guage to it.<br /><br />I am assuming that at high speed enough water is not getting to the head????<br /><br />Want to figure it out before honing the wall?<br /><br />Any thoughts on what to check?<br /><br />Help would be appreciated.<br /><br />Thanks

 

[sony2001]

Re: Force 1988 50hp Overheating

Did you change your prop recently?

 

[12Footer]

Re: Force 1988 50hp Overheating

You may have a blockage in the cooling circuit due to corrosion, salt crystalization, or previously injested impeller pieces.<br /><br />I would remove the ignition system to get at the exaust port plate, and pull it.Also pull the transfer plate on the starboard side. You'll need to replace the gaskets for re-assembly, so have them handy, or make your own, if you have the tools and 'know-how' to do so.<br /> You stated the the top cylinder had scoring, but not the bottom? This could be an indication of a partial blockage.

 

[billyjake33]

Re: Force 1988 50hp Overheating

No new prop. Haven't taken apart yet but engine did fire. Should I put thermostat back in when done? Pos/Neg<br /><br />Thanks

 

[billyjake33]

Re: Force 1988 50hp Overheating

OK - Took it apart yesterday found a little oil/dirt on the bottom but that was it nothing in there blocking any passage way. In the process of making new gaskets.<br /><br />Any other suggestions? I know if I take it out again without finding the problem I'll cause more damage.<br /><br />Any help would be appreciated.<br /><br />Thanks