Tohatsu 25C2 Over Heating, What could it be?

[kezguy]

1997(8) model 25C2, starts fine, runs fine for about 15 minutes or so...twice it started to make rattle / knocking sound then shut down..second time it seized up and pull cord would not come out(scary!).. both times after cooling it started fine again...didn't want to push my luck so am switching out impeller...the motor was pumping water but seemingly weak stream and flow did not start right away, exhaust smoke came out of water outlet nozzle , have only had the motor one day.. last owner says only about 30 hours on motor and worked fine last week ..have back flushed after dropping lower unit and water flows freely...old impeller looks ok but perhaps flexed to much??.. IF the new impeller does not resolve problem , WHAT COULD IT BE? Proper spark plugs in place, oil in gas ok..what else?

 

[phatmanmike]

Re: Tohatsu 25C2 Over Heating, What could it be?

check the thermostat, its usually in the head or just above the head. make sure it isnt stuck shut. if all else fails ,take it out and run it like tht for a few mins( not permanently) and see if it changes anything. your impeller should be changed every year, especially were you live . and sand or salt will make those things go bad , quicker. impeller should be flexible, if the old one is "stuck" in the bent shape after you take it out, its bad......<br /><br />is your oil mixed properly, thats the cooling blood for your motor, if its not at least 50:1 your gonna fry something inside. and check you carb , make sure your not running too lean of an air:fuel ratio, remember, without fuel, you get no oil, without oil, your motor is junk. and try not to post 4 different things at once, put em all in teh same post..... its hust easier for us that way..<br /><br />if your engine was knocking from the over heat, it may be too late. i have one that does that and now i have a paperweight <br /><br />m ikey

 

[kezguy]

Re: Tohatsu 25C2 Over Heating, What could it be?

i just got back to this post 5 years later!. The problem was a BUG COCOON! a bug of some sort had climbed into the head thru the upper exhaust port (at rear just below power head case - water comes out AFTER thermostat opens up) and built a "cigar-like" wad of leaves. To figure this out I took out the thermostat and filled the system with "SNO-BOL" toilet cleaner (mild acid) to de-salt any build up. After the foamimg settled down there were black particles which I found odd. I used a piece of #10 braid electrical wire frayed at the end to act like a brush to ream out the system. It snagged the CIGAR and out it came. Damn bug almost cost me some major $$. It worked fine once out and re-assembled.