2006 Yamaha 90 4 stroke overheating

[YK Boater]

I have a 2006 Yamaha 90 4 stroke. Has full power, rides well at full speed for about 15 minutes then the motor does the auto throttle back probably because it is overheating? I ride for a while after auto throttle back then it does it again, another auto throttle back and i have to slow down even more. Keeps happening till i am just putting along on idle. When i stop to cool it off it runs great for like 5-10 minutes then it throttle backs again. I changed the water pump kit & thermostat and it still does that. What else do I need to do?

 

[99yam40]

Re: 2006 Yamaha 90 4 stroke overheating

You need to find out if it is overheating or there is some other problem like running lean, as either one will destroy a motor if you keep running it like that.
Does your alarm system work?
Have you tested it and how?
Do you have any gauges that give a indication of what problem is occurring?
A Yamaha service/repair manual will help a lot in your troubleshooting

 

[YK Boater]

Re: 2006 Yamaha 90 4 stroke overheating

I don't have a tachometer on it. I probably need to buy one. I have heard the alarm go off before, that was when the water intake was covered by grass. I just cleaned it off and motor ran good. So I do know that the alarm does work. When this motor cuts back the rpm's the alarm does not go off. So I don't know if it is overheating or running lean. I do know that when I take off the cover to look at the motor, the engine is very hot to the touch. That is why I thought it was overheating. What do you think I should do?

 

[Kanadakid]

Re: 2006 Yamaha 90 4 stroke overheating

Is water coming out of the pee hole hard ? Run weed wacker string through the pee hole to dislodge anything that is / could be obstructing the flow. 2006 shouldn't have anything serious going on.
Hope this helps

kid

 

[99yam40]

Re: 2006 Yamaha 90 4 stroke overheating

I don't have a tachometer on it. I probably need to buy one. I have heard the alarm go off before, that was when the water intake was covered by grass. I just cleaned it off and motor ran good. So I do know that the alarm does work. When this motor cuts back the rpm's the alarm does not go off. So I don't know if it is overheating or running lean. I do know that when I take off the cover to look at the motor, the engine is very hot to the touch. That is why I thought it was overheating. What do you think I should do?

If you think it is overheating then test the alarm to see if it is doing it's thing now , not in the past

 

[Silvertip]

Re: 2006 Yamaha 90 4 stroke overheating

Keep overheating this motor and you will no longer need to worry about it because you will "toast" it. It is sick. Thermostat stuck closed or Water pump needs replacing are two prime suspects. Do you have a crankcase full of oil contaminated with fuel from "making oil". Fix the overheat alarm.