Impeller water discharge temperature? (Yamaha year 2000 4hp 4 stroke)

[Manoj77]

The impeller discharge from my Yamaha 4hp 4 stroke is a steady rough stream but it gets very hot - almost too hot to touch. New impeller and housing kit was just put in a day after I acquired the motor so I know the impeller is fine plus there is a steady albeit rough stream. Im concerned about how hot the water is and why it isnt a smooth stream even with a new impeller kit put in .Suggestions please? Maybe this is normal for a Yamaha? I used to own a Tohatsu and the water stream was warm but never as warm as the stream from this Yamaha.
Thanks in advance for any help.

 

[renegade15]

Re: Impeller water discharge temperature? (Yamaha year 2000 4hp 4 stroke)

Sounds like what I'm going through on mine, exhaust leak in the midsection is pre-heating the cooling water...I don't know that motor though so I could be way out in left field somewhere!

 

[gejandsons]

Re: Impeller water discharge temperature? (Yamaha year 2000 4hp 4 stroke)

The impeller discharge from my Yamaha 4hp 4 stroke is a steady rough stream but it gets very hot - almost too hot to touch. New impeller and housing kit was just put in a day after I acquired the motor so I know the impeller is fine plus there is a steady albeit rough stream. Im concerned about how hot the water is and why it isnt a smooth stream even with a new impeller kit put in .Suggestions please? Maybe this is normal for a Yamaha? I used to own a Tohatsu and the water stream was warm but never as warm as the stream from this Yamaha.
Thanks in advance for any help.

Had a evinrude v 4 110 HP that was air locked at the manifold that housed the thermostat. Water from the indicator was very hot & so was the engine. I had to loosen one of the two hoses & allow the staem to escape. Once the water hit it it opened the T stat. May not be your problem...just something weird I ran across.

 

[Manoj77]

Re: Impeller water discharge temperature? (Yamaha year 2000 4hp 4 stroke)

i had a well regarded marine mechanic do a thorough look over and he said its fine. The discharge temp is 120 degrees which is well within the acceptable limit etc. Guess I was worrying for nothing. He pointed out that the tell tale discharge hole in this OB is located 'downstream' from the thermostat opening so the water that is being discharged will be of the temperature that the thermostat is rated to open at - in this case 120 degrees. The question that came to mind after I left his shop is what should the thermostat rating be for this OB?