Force 120HP cooling

[deppong]

Is there something I'm missing here - other than its a Force engine. The darn thing <br />runs great its just so touchy when it comes to keeping it cool. Last week I was in a <br />Lake - got into a slightly weedy area and the darn thing overheats. When I got it home<br /> - took the lower unit off ---- theres nothing in the pump and the pump looks fine.<br />Dont see any excessive wearing (pump is only a year old). <br />Put a hose on the intake tube to the block and the water is flowing freely out of the<br />exhaust. No blockage there! So what is the problem? Could the weeds have <br />ruined the pump? Is it possible that if water is cut off at the intake momentarily the <br />pump losses suction and you have to wait until the engine cools and try iy again?<br />Anyone have any answers except that the pump is worn out!<br /><br />Thanks!

 

[happyzee]

Re: Force 120HP cooling

Is the overheating problem repetative? i.e., does it happen at idle? No matter what speed?<br />Everytime I hit a sand dune, I get an overheat alarm. But as soon as I get it into clear, deep water it clears and cools ok.<br />Another test is to "Feel" the exhast manifold. If it is "Hot" or getting hot it is overheating. If it feels cool/cold to the touch, it is OK regardless of the alarm (Bad sensor).<br /><br />Let us know

 

[Dan K]

Re: Force 120HP cooling

I own a 120 Force I bought new in 1994. Every now and again the dam heat alarm would sound for no reason. I've changed impellers, impeller housings and thermostats which seems to do the trick for a while. The two large holes at the rear coming out of the exhaust housing are called idle relief ports. Water pumps out like crazy at idle but stops when I take off. This didnt seem right to me so I installed a pisser for about 5$. 1/8 pipe 90 degree fitting into threaded hole just above thermostat housing connected to 7/32 hose and into a pisser from a 20 hp merc or something similar. now if the alarm goes off, you know for sure if it's pumping water or not.I don't know why this wasnt a factory install because it works great and takes out the guess work. by the way, a proper water pressure guage is 80$ Canadian.

 

[deppong]

Re: Force 120HP cooling

HappyZee and Dan K - thanks for the input. The engine was definitely HOT - steam was coming out of the pee holes and the alarm sounded. I know the alarm is good. Did not want to take a chance on runing the engine. If it was clogged I would see symptoms associated with it - but I dont. It could be that there is some type of air blockage keeping the water from circulating. These Water pumps really astound me - such antiquated technology<br /><br />Dan K - I like the idea of attaching a tube to that 1/8 NPD connection - maybe that will eliminate the airlock if there is one.<br /><br />Like I said - it was working fine all day - once I got into the weeds - not really thick weeds - thats when everything happened. The person that gave me a tow was going thru the same weeds with no effect on his motor. He had it trimmed up - maybe that was the differenting factor. Anyway thanks for the ideas!