1996 Yam 250 overheating

[Manta]

Hi,<br /><br />I had a new water pump installed. I then ran it for an hour at 4000 rpms, stopped to get fuel, started it up and ran at idle through a canal for 5 minutes when the alarm went off. Yesterday, I was moored all day, ran at idle for 5 minutes as I pulled up anchor and the alarm went off again. I put it in neutral and raced the engine at 2000 rpms and the alarm stopped both times. There was no obvious weed in the water. What could this be from? Help!!!

 

[rodbolt]

Re: 1996 Yam 250 overheating

time to service the pressure control valve.<br /> clean the pocket with a scraper/pick and replace the grommet.

 

[Manta]

Re: 1996 Yam 250 overheating

Thanks for the response!! Where is the pressure control valve located? Can a mechanically inclined guy like me do that? Does that mean I'll have to haul the boat out of the water?<br />Thanks again!<br /><br />

Originally posted by rodbolt:<br /> time to service the pressure control valve.<br /> clean the pocket with a scraper/pick and replace the grommet.

 

[swist]

Re: 1996 Yam 250 overheating

I just did this operation myself on the same engine - I'm mechanically skilled, but without specific knowledge of outboards and I did it with no problem.<br /><br />The valve is located on the back of the engine, underneath the electronic control unit box (dome shaped cover connected to big hose held on by two bolts. You may have to push some wiring out of the way, but you can get at it pretty easily. The boat doesn't have to come out unless you can't get at the back of the engine. You will need a new gasket for the cover.

 

[Osprey]

Re: 1996 Yam 250 overheating

The Pressure control valve is down low on the starboard side on the back of the powerhead. It looks like a small thermostat housing with two retaining bolts and an inch or so diameter black hose connected to it.<br /><br />Under the housing is a large spring, a plastic valve piece and a rubber grommet which is installed in the engine block. Carefully remove the grommet and as Rodbolt describes use a dental pick or small screwdriver to scrape out the corrision under the grommet and inside the housing cover. Be careful when re-installing the grommet to not push it all the way thru and lose it in the engine block.<br /><br />Pickup a new housing gasket ahead of time. Also Yamaha has a retrofit plastic valve part thats shaped like a mushroom and seats against the face of the grommet only rather than having fins that enter the grommet.<br /><br />If you don't have access to the back of the engine from a swim step, etc, this would not be easy to do with the boat in the water.