Yamaha 225hp Temp Alarm

[Fishballs15]

Hello all -

New Grady owner here as of late July. Boat is a 1993 Escape with a '93 Yamaha 225hp outboard and I'm having a little trouble with the temp alarm going off after using the engine for a bit. Example, ran the boat approx. 5-6 miles at three-quarter throttle with no issues, but then throtle back to cruise at 8-10 mph for a bit and then temp alarm goes off. Done this twice now and after each time, I shut down the engine, let it cool and then restarted and returned to harbor with no trouble. Previous owner had impellor replaced a few months ago - any ideas on what may be causing this issue? Any advice on where to start? I should add that it is pumping water and oil so I thought this was a little strange.

Was hoping to get a little more use out of the boat before pulling from water and taking to dealer for a good once over as the boat is new to me. Appreciate any advice.

--Fish

 

[seasick]

If the telltale stream is strong, the pump is probably OK. I would check the poppet valve first and hopefully that is the issue. If the valve sticks open, water flow is reduced at low speeds.

 

[Fishballs15]

Thanks. I haven't picked up a manual yet for this engine, but is the poppet valve doable with the boat in the water or am I asking for trouble? Anyone have experience with the poppet valve location on this motor? Any and all input is appreciated. Sorry the for twenty questions...

 

[seasick]

From the diagrams, it appears to be on one of the heads. I am not sure which one.It is in a housing that looks like a thermostat housing but this one has an outlet with a hose connected to it. The cover is held on with two bolts and there is a gasket, spring, valve and bushing under the cover. It can be removed in the water but don't drop parts into the briny.
Make notes on the position and orientation of the parts.

 

[BobP]

You may want to take this one in to your local Yamaha dealer for a diagnosis.

You risk wrecking powerhead continuing to use motor, I'd say between $5-7K for new powerhead.

 

[Fishballs15]

Thanks for the replies. I'll do some more investigating and see what turns up.

Much appreciated.

-Fish

 

[wrobinson]

Depending on what gauges you have you may be able to change the display to get a look at your actual engine temp. That way you would know if it was actually getting warm or a faulty sensor, etc.

 

[seasick]

Depending on what gauges you have you may be able to change the display to get a look at your actual engine temp. That way you would know if it was actually getting warm or a faulty sensor, etc.

If the sensor were bad, how would you know that from the display reading??? You wouldn't know if the temp was truely high or the sender was bad.
In addition, the fact that the temp is OK at speed is a a clue that the sender is OK since in general when everything is working correctly, the motor generates less heat at low speen than at high.

 

[shadow379]

One of my co-workers just had the same problem, he replaced impellers and had a temp alarm as you have described on both of his engines. He used the Sierra parts instead of genuine Yamaha..Took them out and replaced with the genuine Yamaha parts (Which look exactly the same by the way) and it cured the problem. Hope this advice helps!

 

[Fishballs15]

All - appreciate the new input on this. As an update, I've run the boat a couple more times, but in short runs. Kept each trip under two miles or so and then stop for a bit and fish or take the family to the beach. No temp alarm thankfully.

Good point on the impeller and genuine Yamaha parts. I don't believe the "new" impeller is true Yamaha replacement. Will have that checked this fall at the dealer along with several other items like the poppet valve.

-Fish

 

[Lainie J]

I had a very similar issue last season on one of my F225. I had the impleller changed not original Yamaha parts, had low water pressure. Had the mechanic replace with original as i watched him do it and the pressure was then normal no isues.