force powerhead swap

[kseely65]

Could someone help me out and tell me if I could put a 1998 force 90hp powerhead in a 1990 90 hp motor? I have an oppurtunity to get a good 1998 powerhead to replace my need to be rebuilt motor. This would be a good, cheaper alternative. From the pictures of the 1998, it looks identical. Any help would be appreciated.

 

[Foose57]

Re: force powerhead swap

Yes , yes I think it will work , may need glue !!!

 

[walk-on]

Re: force powerhead swap

I was waiting for a reply from one of the experts on this one. I looked at the blowups on crowleymarine.com and it does not look like the adapter plates are the same for the different models. If this is indeed true then the powerhead will not match up with the lower unit.

 

[kseely65]

Re: force powerhead swap

Ok, thanks, I looked up the gasket kits for both years and it showed the same gaskets for both year models with an additional 2 gaskets for the 1998.I was thinking that the additional 2 gaskets were for adapter plates that was added to bolt up to the newer lower unit, but wasnt sure. It also looks like the area around the fuel pump bolts up is also differant from the pics I recieved. If you hear that it would still work, let me know. Thanks

 

[Frank Acampora]

Re: force powerhead swap

Oh, yes! You can put it on, but it aint gunna work! Mercury changed the driveshaft and crankshaft splines. You MAY Be able to substitute a Mercury two piece drive shaft--if your engine has a two piece shaft, but they are difficult to find and horribly expensive new. And, I don't know if Merc changed the length of the midleg, so the Merc drive shaft may still not fit.

NOW: If you wanna go through the trouble of swapping your crankshaft into the 98--and I'm not sure they kept the rods and bearing sizes the same-----

 

[kseely65]

Re: force powerhead swap

Thanks guys, I think I will probably either go with a rebuild of my existing powerhead or possibly find another used one. I kinda had an idea that the crank would be differant lengths due to the adapter plates. It was an idea though.