overheating 250 yamaha

[perhaps125]

I have a 33' center console. Port motor overheats at 4000 rpm. Entire new water pump assembly, and power head. Switched the motors and the overheating followed the side of the boat, not the motor. Must be sucking air. I have owned the boat for 18 years with no problem. Help please.

 

[SpinnerBait_Nut]

Re: overheating 250 yamaha

Welcome to iboats.
This needs to be in the Yamaha&Suzuki Outboard Troubles/Repair

 

[andy6374]

Re: overheating 250 yamaha

Are the motors spaced evenly athwardships from the keel and are they the same height above the keel?

Do you have water pressure gauges on the motors? If so are they reading different pressures.

 

[JUSTINTIME]

Re: overheating 250 yamaha

poppet valve or a transducer to close causing ventilation