Merc 60 6hp pump impellor

jeepking1

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Joined
Apr 19, 2009
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6
I need help with a water pump problem. I replaced the pump impellor and it does not pump water. I have pulled the lower unit off for the 3rd time now to try and figure it out. It looks like the impellor may not be seated clear down in the pump cup, but the top housing bolts into place ok. I would think as long as it is bolted down, the the impellor would have no choice but to seat all the way down. Last time apart, I spun the shaft with a drill motor while the lower was in a bucket of water. very small volume of water came out the tube, but I just figured it was cause the drill was slow. I did make sure the impellor was bent in right direction upon installation. It is the same as the old one that came out. It blows exhaust out the water hole, just no water. I hav er run it in both a water tank AND with a garden hose attachment with the same results either way.

Ok, background on motor. According to the serial number, this motor is a '61 Merc 60 6hp. It last ran in 1989. Been stored indoors since. Other than always running the carb dry on shutdown, no long term storage prep was ever made. Drug it out a few weeks ago, pulled the plugs and cleaned them, then poured a little Marvel Mystery Oil in the cylinders and turned the motor over a few times. Hooked up the fuel line and she sputtered on the 3rd and started on the 5th pull. Motor still runs good, pump impellor did not.

Any ideas will be appreciated.
 

saumon

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Aug 2, 2004
Messages
1,452
Re: Merc 60 6hp pump impellor

Did you put the key onto the driveshaft?
 

jeepking1

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Joined
Apr 19, 2009
Messages
6
Re: Merc 60 6hp pump impellor

Yes, the pin is in place. However, the impellor can not be pushed all the way down by hand, I have to tighten the pump top down on it to seat it.
 

saumon

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Aug 2, 2004
Messages
1,452
Re: Merc 60 6hp pump impellor

What's your serial #?

Maybe you ordered the wrong impeller, cause it should be pushed all the way down and the pump housing doesn't have to put pressure on it. Did you turn the driveshaft clockwise when sliding the pump housing onto the impeller?
 

jeepking1

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Apr 19, 2009
Messages
6
Re: Merc 60 6hp pump impellor

Yes, I checked that it was right for the clockwise rotation. I double checked the serial number and part number on oldmercs.com and they are correct. Plus, I held new and old side by side and they are the same.
I did just notice that maybe the drive pin was not settling into the new impellor the same way, so I shortened it up a hair and I finally got the impellor to drop into place and seat all the way. I could even see on the old impellor where the pin had been bulging out the side a little. Maybe not even the right pin, but it seems to work for now and I'm selling the motor anyway.
Now I just need to re-assemble the lower and see if it pumps water now. I'm hoping the odd pin fitment was maybe deforming the impellor enough to keep it from sealing and pumping.
Serial # 1438467
Impellor # 47-22748
 

qz5kbk

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Joined
Sep 22, 2009
Messages
11
Re: Merc 60 6hp pump impellor

I bought a 1962 Mercury 6.0hp (MK6A) back a few years ago and first thing I did was change the impeller. I didn't have a problems assemblying the water pump, but I was always concerned with the amount of water that actually was discharged from the exhaust. The exhaust opening is large enough to stick your little finger in, but on my unit, it just spits out a small amount of water (even while running at a close to WOT).

I know this doesn't help you, but thought I'd just mention it. If anyone is familar with this design of outboard, is this common? Maybe the design of the pump doesn't create a great vacuum and what you get is what you get?!
 
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