1993 model Force 90 HP

[Charlie T]

I just had a 1993 90 hp Mercury Force installed on my 18 ft heavy-duty aluminum hull and it would only rev to 4400 rpms. I would like to find out what it should turn and is there any way to get rid off or bypass the "funky" looking exhaust fin near the prop to be able to runa standard blde prop? The prop that came with the motor has cut-down blades to clear the exhaust fin. Any guidance would be appreciated.

 

[roscoe]

Re: 1993 model Force 90 HP

5000-5500 rpm is recommended range.<br /><br />There were alot of variations in those motors from model to model, even within the same year. It is best to id the motor by the model number and serial number when posting questions about it.<br /><br />There were 4 different lower units used on that motor, as far as I can tell. All used the exhaust snout. You need it to direct the exhaust away from the prop, or it will ventilate.<br /><br />There are props available for you motor that will work without modification.<br /><br /><br /> http://www.boat-props.com/propellers/s

 

[Charlie T]

Re: 1993 model Force 90 HP

The rpm range is what I expected, however the serial number has faded away on the base. It just says mercury marine force on it. The cover was painted black and there are no identifiable HP markings. I was told that it was a 1993 90 hp. Is there any way to identify exactly what the serial number/HP is?<br />Thanks for the info.

 

[roscoe]

Re: 1993 model Force 90 HP

The id tag is the only place the numbers appeared. <br /><br />Here is a link to the lower unit on that motor.<br />Notice there are 4 different versions, A,B,C, and D.<br />If you compare your motor to the diagrams, you can atleast determine which lower unit you have.<br /><br /> http://www.mercruiserparts.com/Show...4/53.png&inbr=1468&bnbr=29&bdesc=GEAR+HOUSING <br /><br />Other component groups are accessable thru the links at the left edge of the page. <br /><br />Good Luck