Nissan 6HP waterpump issue

[nickbowman]

I have a Nissan four stroke 6HP (6A2) that I use in a mix of salt and fresh water (located in Seattle). I've had the motor about 5 years and even though the water was circulating fine I figured that it was past due to replace the water pump impeller. I replaced the impeller based on some of the older posts on the site (thanks by the way) and everything seemed straightforward, but the water exiting the upper unit is now down to occasional drops instead of a steady stream.

Here are my 3 ideas so far:

- I scraped out some of the salt residue in the entrance of the water pump, perhaps a piece was dislodged and got stuck further up the near the water exit. I will check that with a wire when I am back at the boat.

- Maybe the impeller is not spinning. I don't think that this is likely, I spun the impeller with the shaft as I was re-attaching the top of the water pump .

- There is a leak in the path that the water travels through the water pump and out the motor. This is the option I am leaning toward. Everything seemed to re-attach fine, although I couldn't necessarily check how well the water pump exit seated to the tube leading to the upper unit, I could only see that they mated as I re-attached the lower unit.

I noticed that my lower unit is filling with water (and bubbles come out of the rubber grommet) when I lower my motor and run it. Is this normal? I guess it may be, but I never noticed it before.

Unfortunately none of my local dealers had a factory service manual, so I'm currently waiting as one is shipped to me. If anyone has any thoughts or tips on this, I'd really appreciate it!

Thanks,
Nick

 

[pvanv]

Re: Nissan 6HP waterpump issue

Always change the entire wp kit, not merely the impeller. The job will last a lot longer.

You probably have some crud in the telltale. Run the motor (in water of course), and probe in the outlet with a stiff wire or fishing line and it should come clear, and the crud be ejected with the water stream. The NSF 4/5/6 has a staggered outlet chamber for the telltale, and crud can get lodged in there.

If you weren't pumping, steam/exhaust would exit from the telltale. Since you aren't seeing that, you are probably pumping, but the telltale is likely just clogged.

If the water tube is not inserted into the upper wp housing, the pump will just fill the exhaust housing.

The grommet that is the access cover for the shift linkage closes off the exhaust housing. That chamber will have both water and exhaust in it whenever the motor is running in the water. So that's normal.

 

[nickbowman]

Re: Nissan 6HP waterpump issue

It was crud in the telltale, came out after about 3 seconds with a paper clip. Everything is looking good, thanks for your help!