Help Yam. 150 Overtemp alarms, my 2530, mech can't find

[Cant Parker]

Hi Guys

Well a mystery... Hopefully there is a really experienced expert Yamaha mechanic out there who can help. This is a total pain. My 2005 2530 with twin 150 4 strokes has an intermittent overheat alarm (on both engines) that goes off intermittently and only when putting the throttle forward (or reverse) from idle. To date, my mechanic has replaced.. impeller pumps, impeller housings, thermostats, filters on engine, just put in diodes under the dash (from Japan.) fuel water separators and engine temperature sensors. The diodes were replaced because he found low power to the dash which they helped that but I still have the issue. The readouts on his lap top show no actual temperature issues. The engine temp sensors were replaced as a bit more of a preventative maintenance and to rule them out. This is a real pain.. as it usually happens when docking or putting the boat on the trailer. Also, it happens on both engines, not just one, whenever it feels like it.. To stop the noisy alarm i have to shut off the engine and restart. That stops it.. until it intermittently decides to do it again..

Any advice or help would be appreciated. I live in San Diego.

thanks
Doug

 

[Cant Parker]

No advice?

 

[kidfreediver]

Solenoid, I don't know

 

[Cant Parker]

thanks anyways

 

[SC21]

Has this been kicked up to Yamaha USA? What does the factory rep say?

 

[jzumi]

I had sorta the same issue on my F250. It would send the overheat alarm at various random times while idling.

Turned out that changing the poppit valve did the trick after changing the impeller, sensor, etc did not solve it. The poppit valve controls flow of water to the upper part of the motor and is supposed to increase flow at low rpms.

My mechanic thinks that the old poppit would occasionally send low flow just enough to trip the sensor even though the computer would not detect much of a temp rise at all.

Good luck.

John

 

[Cant Parker]

I placed a call to Yamaha today and will get my mech. to talk with them direct.

Also, thanks for the solenoid idea I will pass that on.

Thanks for the help!

Doug

 

[Brent]

Has the poppet valves in the cooling system inspected or replsced? They maintain water pressure and open up when the motor Roma increase.

 

[Brent]

Also some Yamaha outboards have internal corrosion in the mid section. Google it but have not read about it in 150

 

[Cant Parker]

Pretty sure I understand thanks, but did you mean?

....motor "rpms" increase.

They maintain water pressure and open up when the motor "Roma" increase.

Thanks much
Doug

 

[Brent]

Yes as temps increase the poppet valve opens . On 225 it is easy to access

 

[Cant Parker]

thanks, gave him the info. Ill let you guys know. appreciate the help.

 

[Cant Parker]

So my mechanic went all through work performed and discussed with a more experienced mechanics. He has 3 possible issues

Poppet valves - clean and clear but could replace at $30 each

Oil sensors (a rash of them have been replaced by techs) $200 each

Multi engine control unit $500 each

Q- Isn't there a way to narrow this down through testing or some other method?

 

[Brent]

I feel the Yamaha diagnostic software is useful but not all encompassing on 02 225. It does not have enough sensors . Maybe email Andy at SIM Yamaha

 

[Brent]

A certified Yamaha mechanic might help along with access to service bulletins