impeller change

[Wanderlust]

I have a Westerbeke 21A in my MKII and dont know when the impeller was last changed. (I have owned Wanderlust for only 6 months). I think its pretty straightforward but... the gasket that was sent with the new impeller is very thin, like paper. Does one use permatex or silicone of anything on the new gasket??

[seadog6532]

I used permatex on my MD7A. It came with 2 paper thin gaskets and I put one on the pump housing and the other one on the cover, both held in place with permatex and don't have any leaks at the pump.
The impeller needs to be close to the cover to work correctly. That's why the gasket is so thin.
I don't like silacone because in many cases it will keep anything else from sticking if you use it first. Especaly if you use it on wood, but I don't like it one the motor either.
Hope this helps.
Mark

[Steve Laume]

I had changed my impeller a number of times and only ever used one gasket with no additional sealer. There were never any leaks, the cover and gasket was easy to remove and could be replaced again. I has used my boat in very cold weather and find that it is hard on the impellers. If you ever had to change the impeller in less than ideal conditions you might not want it to be glued in. This is merely another train of thought not a condemnation of Mark's method. He has the some added security of knowing there is no chance of it leaking.

I did have a shaft seal leak on my raw water pump last year and rather than rebuild I replaced it. The new pump has an O ring seal thereby eliminating all gaskets at impeller change.

Be sure to keep your old impeller if it looks okay for an additional spare, Steve.

[barfwinkle]

Steve Wrote:

If you ever had to change the impeller in less than ideal conditions you might not want it to be glued in.

Steve makes a very important point here. You need to be able to replace your impeller in a matter of minutes. IF it fails in a busy channel, or in a strong tidal flow, having to take the time to clean the "mating" surfaces in order to get a good seal could be very valuable time lost!

Another thought is to install a Speed Seal. I put one on Rhapsody and I love it. The last time I had to do a change we were in rough water, but not other jeopardy, and it took me less than five minutes to get the new impeller on and the engine running. I was very pleased.

JMTCW!

Happy Thanksgiving to ALL

[Steve Laume]

Before I would spend the money on a speed seal cover for an Oberdorfer raw water pump you might consider the cost of replacing the entire unit. One of the things my surveyor told me to keep an eye on was the 20 year old shaft seals on my raw water pump. A couple of years into my ownership I noticed a very slight seepage. Faced with an expensive rebuild kit vs a new pump, I went for the new one. It had the added advantage of an O ring seal. It does not have the big thumb screws like the speed seal but I always have a screwdriver handy. you could buy the bronze knurled knobs if you had your heart set on them. Unlike the speed seal cover the O ring is in the pump body. This gives you the advantage of being able to polish or flatten the cover if the impeller wears it with use. The biggest pain with impeller changes is the foolish split ring that keeps it on the shaft.

Happy Thanksgiving to all.

Keep the water flowin, Steve.