Over Heating Yammie 1992 150 2stroker.

[Monkey Butler]

It is on the lower right of the exhaust cover on the back of the powerhead. It's the thing that looks like a thermostat housing in this picture.

http://www.monkeybutler.com/boat/yam...n/IMG_4548.jpg

There is a rubber grommet in there that you should replace as a maintenance item along the same schedule as your t-stats. Also, Yamaha changed the design later on so it was less likely to get stuck open by debris like sea grass. If you go to

http://www.yamaha-motor.com/outboard/parts/home.aspx

and browse to your motor look at the tab for "CYLINDER CRANKCASE" and parts #48 to 51 will get you the new design.

Also, if the pump was just done then when you pull the lower unit check to make sure that the rubber grommet that the water tube plugs into up in the mid section is in place or you could lose water pressure there too.

Steve P.

[willy]

Thanks, something else for me to check this weekend.
And the pump was done before last season, something happened since the last time I had it out, four weeks ago and today.
Now I did use flush away on the motor, I have the flush system that you attach to the hose. I am wondering if something could have gotten dislodged from the flush and cause a problem. Just reaching for ideas I guess.

[phatdaddy]

willy, i've got a 150 yamaha on a 19' cc and it does the same thing. if i run it on the hose, the horns go off after 10 minutes. i run it on the muffs & a hose to the flush port, no problem. i know its a pain, but try puting it it the water and see if it repeats.

[spareparts]

Yamaha recomeds using the flusihng attachement and the ear muffs , both connected to a dedicated water supply when running their V6's on a hose. Teh Yamaha water pumps have several places(water drains) that will suck air when you run it on a hose. Try using the flushing attachement and the muffs, see if it overheats then. Worse comes to worse, take it to the boat ramp and stick it in the water

[Blue_Runner]

Good info. I don't like running mine on the hose because it doesn't seem adequate. I think I use the double hookup idea going forward. I know you should NOT crank the engine using just the flush attachment...I read that in the manual after a friend said it is ok. Can't believe everything you hear.

[willy]

Well I am going to change out Tstats because I have them out already and try it in the water first as all advise. Come to think about it I was in full hot sun and it was running for at least ten to fifteen minutes when it happened so hopefully that is all it is.
Say a prayer

[RABBITFISH]

Well, I can relate to this problem. Was having the same issue with mine, changed water pump, thermostats, still having overheating. Found out about the PRV valve. Took it out and cleaned it, replaced it. NO MORE PROBLEM!!! Worked like it originally did.. There was not much in the way of dirt, just a little sand, but enough to keep it from making the proper seal. Simple fix and made me more confidant in my motor.. Let us know what does it for you!!!