Re: 90hp force -what year model,rpm,prop size
Mercury bought Force from the USMarine bankrupcy sale in 1989?. They kept the Force product line and name to provide an economy line of motors. But they also knew they needed to upgrade the Force components to make them more reliable.<br /><br />The surefire way to verify you have a 1995 model, is to look at the lower unit, directly above the prop. If you have a small flat trim tab, round disc with a fin pointing downward, you have a 1995 or newer.<br /><br />If you have a large hollow fin, which is called an exhaust snout, you have a 1990-1994 model.<br /><br />The 1995 model would have a Mercury lower unit, charging and ignition system, lots of little parts, a Merc tilt and trim unit, and upgraded carbs I think.<br /><br />You can get most if not all parts from a Merc dealer.<br />Always supply the dealer with the model number when ordering parts.<br /><br />No Merc dealer where you are located? Then you can order them directly from Merc at
www.MercuryPartsExpress.com<br /> Or from
www.MercruiserParts.com ( the same Mercury parts at a 10% discount )<br /><br />The prop you have is allowing the rpm to go a bit high, but it is not too bad. Afterall, you are pushing a pontoon and the extra thrust is nice. IF you need to replace the prop, you might want to increase the pitch by one inch. But you should be ok as is. You will Not get better performance by changing the prop, unless yours is severely damaged.<br /><br />130* is the temp at which the thermostat opens, so it is not unusual for the motor temp to be slightly above this. Did you actually inspect the thermostat to see if it is a 130*?<br />Someone might have put a 143* therm in by mistake.<br /><br />Change the waterpump impeller annually, and decarb the motor every fall, and it should be good.<br /><br />Click and read this:
http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000016 <br /><br />These motors are pretty basic and easy to work on, well, except for syncing the carbs.<br /><br />Known failures are the impeller causing an overheat .<br />I have a Water Pressure gauge on mine, as it will indicate the drop in water pressure immediately. Where the temp gauge will only tell you of an overheat AFTER it gets too hot. So keep a close watch on that gauge.<br /><br /> <br />And the original stators would fail causing the ignition to die.<br /><br />Happy Boating. May your Force live a long and healthy life.