70 hp yamaha overheats at idle

[doghouse1]

Hi

I have a 1996 70 hp yamaha 2 stroke engine. The engine is in great shape with low hours and was used mosly in fresh water. Recently the over heat engine alarm has gone off three times but only at idle. When I give the engine a little gas, the alarm goes off. The alarm never comes on when on plane or higher rpms.

The engine has a new water pump replaced this winter and the thermostat was replaced last year. I have heard that it may be a poppet valve. I do not even know if my engine has a poppet valve. What should I do? What do you guys think?

Thanks in advance.

 

[99yam40]

Re: 70 hp yamaha overheats at idle

Find out if you have a PRV (poppet) is my best advice.
Did you change just the impeller or that kit with plate and cup?

 

[doghouse1]

Re: 70 hp yamaha overheats at idle

I am still having overheating problems. I have replaced the thermostat since it started having overheating problems and the water pump was replaced this spring. The engine runs great, but I still get the overheating alarm only occasionally at a very low idle.

I have heard that this engine does not have a pressure relief valve. What else should I do.

Please help

Thanks

 

[RPierce]

Re: 70 hp yamaha overheats at idle

I have the same 70 hp Yamaha and also sometimes overhead at low idle. What was your eventual fix?

Thanks.

I am still having overheating problems. I have replaced the thermostat since it started having overheating problems and the water pump was replaced this spring. The engine runs great, but I still get the overheating alarm only occasionally at a very low idle.

I have heard that this engine does not have a pressure relief valve. What else should I do.

Please help

Thanks