1969 mercury 3. 9 hp. impeller and housing replaced. stream low

[appleo]

Replaced impeller and impeller plastic housing

More pee squirts at low idle. than at high rev.

Never a strong stream

Thoughts?

impeller key slipping maybe.?

Had it apart 4x and can’t figure what else may cause

 

[rat boat]

It might just be normal. Due to how impellers work, they are more efficient at lower speeds (see attached photo, credit: Evinrude 1966) some times the metal bushing that holds the impeller to the shaft is glued on to the impeller. Make shure that it cant turn or slip.

 

[rat boat]

Also is it a 9HP or a 3.9HP? If it is 3.9, they don't move that much water. If it is a 9HP, dose it have the shifter right next to the engine or in the LU? If it's an upper shifter are your tests in neutral? If so you might want to try in gear.

 

[appleo]

3.9. tested neutral. somebody on this forum mentioned a grommet that may get warped?

 

[rat boat]

did you try putting it in gear?

 

[racerone]

Had it apart 4 times ??-----Found nothing wrong ?----Plastic washer at the very top of the water tube melted.-----Blocking the flow perhaps.----Simple to inspect and fix I think.

 

[racerone]

Does not need to be in gear to pump water.-----Water must be 6" above the pump in a test tank !

 

[appleo]

1 test tank water is plenty high
2 post pic of melted washer location please

ttyl

 

[rat boat]

something like this