Quick and easy water pump question

Joined
Dec 13, 2012
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25
I have a 78' Evinrude 70hp. Just ordered a new water pump, and thought it would come with instructions. But it didnt. :cold:

My question, which direction does the rubber water pump impeller get crammed into the water pump housing?

Its been so long since I took apart the origional, so I cant look at it.
Thanks in advance. :)
 

HighTrim

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Jun 21, 2007
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Re: Quick and easy water pump question

If you have the housing in your hand, upside down, twist the impeller in counter clockwise. If you have the impeller sitting on the driveshaft, and you lower the housing down, spin the driveshaft clockwise while you lower the housing onto the impeller.

Just remember, drive shaft spins clockwise.
 

emckelvy

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Jan 16, 2004
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2,506
Re: Quick and easy water pump question

The crankshaft spins clockwise as viewed from the top.

So, when you've got the pump housing in your hand, turn the impeller counter-clockwise while you're installing it into the housing.

Such that when you flip over the housing, the impeller blades are oriented to be turning clockwise.

Be sure to smear a thin coating of grease or other suitable lubricant in the housing and on the pump plate, where the impeller rides, before assembling.

BTW even if you got the impeller blades turned the opposite way, as soon as you light-off the motor, the blades will flip over, and orient themselves to the proper direction. That being said, it's just good shop practice to have them pointing in the right direction in the first place.

HTH............ed
 
Joined
Dec 13, 2012
Messages
25
Re: Quick and easy water pump question

Does anyone have a trick to getting the impeller over the key? Plus, i dont even know which key to use. I have 2 lower units with 2 different keyways. One has a key slot cut in it. The other (the one im rebuilding) has a section of the shaft machined flat. And im left with a standard half moon key, and a round pin style key.

I know I dont have the impeller upside down. When I set the key on the shaft, and slide the assembly down, the key is a good bit taller (above) the slot in the impeller. I tilt the key to get it started, and the whole key just cams out towards the baseplate. :(
I also have a round pin style key. I dont know which lower unit it came from. But ive tried it also, and short of driving the pump assembly on with a pipe and hammer, that one aint going either.
 
Joined
Dec 13, 2012
Messages
25
Re: Quick and easy water pump question

Well, i got it figured out. I used a soft mallet and tapped the impeller down over the key. Then I used zip ties to squeeze the impeller down. Then I slid the housing down over it. And then reached in with a knife and cut the zipties. DSC02744.jpg

DSC02745.jpg
 

HighTrim

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Re: Quick and easy water pump question

You can also twist the impeller into the housing, then lower it onto the key.

Or, as you push down on the housing turn the drive shaft clockwise. Lubing the blades will help with this.
 
Joined
Dec 13, 2012
Messages
25
Re: Quick and easy water pump question

You can also twist the impeller into the housing, then lower it onto the key.

Or, as you push down on the housing turn the drive shaft clockwise. Lubing the blades will help with this.


Sounds good in theory. But in practice, it was impossible. The amount of force I had to push down on the housing to get the blades to slip inside would have cracked the housing. Not to mention, when I did try this method, just slightly pushing down on the housing caused the impeller blades to pull the oring/gasket right outta the housing. On top of that, the lube I put on the impeller blades was now all over the oring and in the oring groove.
 

Bosunsmate

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Apr 7, 2012
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Re: Quick and easy water pump question

The housing is off set from the centre so you use that to your advantage
 
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