Yam 90tlr 2 stroke overheat issues

[Cogamble]

Have a temp alarm going off on 2007 90tlr 2 stroke. Crank boat in water and within 3-5 mins the temp alarm goes off. Motor is peeing the whole time. Put boat in gear and after few minutes the alarm goes off, back to neutral and then back in gear and the motor runs fine, alarm will not come back on unless motor is shut off and restarted. And then not 100% of the time.

I have replaced thermostat, temp sending unit and water pump rebuild kit with a new impeller. All to no avail. Motor still will get the alarm. Don’t know if there is something else I’m missing that could be causing the problem that I can replace or if I need to take to a shop. Motor has a good stream when peeing.

Any help will be greatly appreciated

[robert graham]

If your motor has auto-lube oil injection then the alarm could be an issue with that system and not motor temperature????

[TownsendsFJR1300]

Might want to check part #39, the pressure control valve.

If it's hanging/sticking open, it'd be an issue:

https://www.boats.net/catalog/yamaha...nder-crankcase


Capture.JPG

[Cogamble]

If your motor has auto-lube oil injection then the alarm could be an issue with that system and not motor temperature????

Temp light comes on with the alarm, if I unplug the temp sensor the alarm and light goes off. Oil light never comes on, unless I’m not understanding the oil lube feature

[Cogamble]

[QUOTE=TownsendsFJR1300;n230436]Might want to check part #39, the pressure control valve.

If it's hanging/sticking open, it'd be an issue:

I pulled the pressure control valve and cleaned all of that as well. Not sure how to tell if it is sticking.

[robert graham]

Is your motor run in saltwater mostly? ....if so, maybe salt build up inside cooling passages....how did the thermostat and pressure control valve look when you had them out?...if salt is in the motor maybe flush system with a chemical salt remover....

[Cogamble]

Is your motor run in saltwater mostly? ....if so, maybe salt build up inside cooling passages....how did the thermostat and pressure control valve look when you had them out?...if salt is in the motor maybe flush system with a chemical salt remover....

Nothing but freshwater since I’ve had the boat the last 3 years. Thermostat and pressure control valve was a little rusty looking but cleaned up well. Thermostat opened up in a pot of hot water

[99yam40]

Nothing but freshwater since I’ve had the boat the last 3 years. Thermostat and pressure control valve was a little rusty looking but cleaned up well. Thermostat opened up in a pot of hot water

at what temp did it open, and what temp did it close back off.
need to make sure it does these thing according the the specs

[Cogamble]

at what temp did it open, and what temp did it close back off.
need to make sure it does these thing according the the specs

It was between 170-180 degrees when I noticed it open

[robert graham]

So it never did this before and now all of a sudden it’s the temperature alarm is going?.....what changed?.....any work done on the motor?....

[Cogamble]

So it never did this before and now all of a sudden it’s the temperature alarm is going?.....what changed?.....any work done on the motor?....

No work done on motor, only thing was a water pump kit and foot grease in spring of last year. I’ve had the boat for 3 years. I may just go ahead and replace the pressure control valve and spring and see if that helps. Other than that not sure what else I can do without a shop

[TownsendsFJR1300]

It was between 170-180 degrees when I noticed it open

Those temps seem a bit high.

From my F150 manual:

I'd be replacing that thermostat if your temp #'s are accurate..



Capture.JPG

[Cogamble]

Those temps seem a bit high.

From my F150 manual:

I'd be replacing that thermostat if your temp #'s are accurate..



Capture.JPG

Thanks, may as well replace it again while I have it apart to replace the pressure control valve