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

appleo

Petty Officer 1st Class
Joined
Jul 19, 2012
Messages
388
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

Seaman Apprentice
Joined
Oct 26, 2019
Messages
40
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.
 

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rat boat

Seaman Apprentice
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Oct 26, 2019
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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

Petty Officer 1st Class
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Jul 19, 2012
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388
3.9. tested neutral. somebody on this forum mentioned a grommet that may get warped?
 

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racerone

Supreme Mariner
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Dec 28, 2013
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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

Supreme Mariner
Joined
Dec 28, 2013
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37,678
Does not need to be in gear to pump water.-----Water must be 6" above the pump in a test tank !
 

appleo

Petty Officer 1st Class
Joined
Jul 19, 2012
Messages
388
1 test tank water is plenty high
2 post pic of melted washer location please

ttyl
 

rat boat

Seaman Apprentice
Joined
Oct 26, 2019
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40
images
something like this
 
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