engine trouble

[fredstubs]

i have 2 yamaha outboards 225hp, salt series vx, 2 stroke. on a 27 foot sailfish '97

the temperature alarm goes off when i am running at rpm 5-6, when leaving or returning to dock. at high rpm boat runs fine.

also when alarm sounds we can sometimes restart the motor and at others it doesn't restart.

i wonder if any one has any ideas on what i could do to fix this problem.

thanks

 

[ocnslr]

Is the alarm going off on both engines, or just one?

How are the telltale streams at that low RPM?

When did you last change the water pumps? entirely or just impellers? This is important based on hours, or months/years.

Are you usually operating in clean water, or water with a good bit of suspended junk or sand?

Have you gone through heavy mud or sand recently?

Brian

 

[Barlow46]

Fred,

What are your gauges telling you? Temperature or oil flashing? Also, are you saying the alarm only goes off at low rpm and is ok at high rpm? What maintenance has been done in past two years with regard to cooling and with regard to cleaning oil filter at remote oil tank?

 

[Grog]

It could be the water pumps or poppet valve. If you aren't sure when they were changed do both and the thermostats. As for why it doesn't start sometimes, I'm not sure if the temp locks out the starter but check the connections anyway.

Also check the oil filter at the bottom of the oil tank and check the oil at the bottom, it can save you a lot of $.

 

[hotajax]

Temp Alarms

This sounds just like a problem one of our members from Boston area was having until he replaced the poppet valve. Rumor has it that it's a simple job, easier than taking out the trash.

 

[choogenboom]

I had the same problem on my 1994 Yamaha 250. The problem was the thermostats. There are two thermostats, one each for each cylinder bank. In my case one was stuck open and one was stuck shut.

Get new thermostats and gaskets from www.boats.net. All you'll need is a 10 mm socket wrench to replace them - if you are lucky its a 10 minute project. One of my bolts was frozen and I broke the head off. I had to drill it out as even ez outs did not work.

At a later date I also had to replace my poppet valve and valve cover. If you can believe this, the cover corroded through from the inside out until I had a raw water leak under the hood. But that came later. Replacing the thermostats was the cure for the sporadic over heating. I am not sure what the symptoms are of a stuck poppet valve.

As a side note, when I had my boat in the local marina for service last year they asked "did you replace the thermostats yet?". I take that to mean its a common problem.

Good luck,
Chris

 

[plymouthgrady]

same issue a couple years ago. Buzzer went off trolling, idling, when at low RPM's. I am confident it's the poppet valve. Easy, cheap fix.