Changing Raw Water Impeller

[vineyardsailor]

Can anyone tell me whether you have to remove the pump from the engine to change the impeller. From the (vague and confusing) instructions, it would appear to me that you can simply remove the pump cover and replace the impeller. I have the impeller kit but it does not contain the pump to engine gasket nor the seal. Just removing the cover may require some fiddling but looks a lot easier than removing the entire pump.

Thanks in advance

[KenKrawford]

Changing the impeller is fairly simple. You definitely do not have to remove the pump from the engine - only the housing that holds the impeller.
Remove the 4 bolts that secure the pump housing to the engine. These are on the back side of the housing so you are working somewhat blind but not terribly difficult. Once the bolts are out, the housing should move forward fairly easily. In order to gain access to the impeller, I found it easier to remove one of the hoses from the pump housing. If you have only the impeller, you should be able to reuse the O ring that is on the face of the pump. Depending on condition, the paper gasket may or may not be reused.
Hope this helps.

[Chips Ahoy!]

Nope...you don't have to remove the pump.
Undo the supply and discharge hoses...just loosen (weird word) the clamps.
Work the two hoses free.
Back out the bolts from behind...I hate that. 7/16 if I remember correctly.
Pull off the cover.
The impeller's blades...as you look at it in the housing...skew to the right...clockwise.
Remember that.

There is a plate...remove it...clean it up and put the "papery thing" behind it.
Put everything back together...duh!

As you assemble twist the blades so they swoop to the right.
Squirt some detergent, grease..whatever before you lock it down.

Can anyone tell me whether you have to remove the pump from the engine to change the impeller. From the (vague and confusing) instructions, it would appear to me that you can simply remove the pump cover and replace the impeller. I have the impeller kit but it does not contain the pump to engine gasket nor the seal. Just removing the cover may require some fiddling but looks a lot easier than removing the entire pump.

Thanks in advance

[vineyardsailor]

Thanks for the responses

I did indeed change it without removing the pump (as instructed to in the engine owners manual)

It went quite easily and with no surprises

I found the manual in this case to be of very little value. I will construct a letter and forward to Westerbeke.

Thanks Again,


Vineyardsailor

[TBOT422]

Replacing the raw water impeller for the first time. I was successful in removing the impeller cover by removing the 4 screws that hold it on. (Who was the bright engineer that decided these bolts need to be inserted from the engine side of the pump?) I'm not sure how easy it will be to get them threaded back into the cover when re-assembling. I'm actually considering drilling out the tapped holes in the cover and using through bolts.

There seems to be no easily visible wear or degradation on the impeller blades. The engine has about 800 hours on it and had 440 hours when we bought it 2.5 years ago. I'm not sure if or when the impeller might have been previously replaced. I'm just going through the maintenance along with several other maintenance jobs this winter.

My question is should I be concerned about the wear on the wear plate? There seems to be a few thousandths of wear on the plate where the impeller runs, maybe 0.003 to 0.006? Is this an issue? Should I replace, clean, buff or polish the wear plate before installing a new impeller?

How often do you need to replace or inspect the impeller?

Thanks

[wolfe10]

Gary,

Polish it. Sheet of glass (really flat surface). Sheets of wet-dry sand paper used WET. End with 600 grit. Continually change orientation of plate so you don't wear down one side more than others-- I do 10 strokes, then rotate 90 degrees. Keep the plate flat and sandpaper wet. Wear gloves or sand your finger tips!

Been there, done that (many times through the years on different boats).

Brett

[TBOT422]

Brett,

Wouldn't it be easier to just turn the plate over and let the new impeller run on the other side of the wear plate? It would certainly be a lot easier to polish the back side than the side with a 0.004 to 0.005 groove cut in it.

Thanks

[wolfe10]

Gary,

Yes, if this is the first time the impeller has been changed. But next time will require plate replacement of refinishing as both sides will be worn.

[TBOT422]

Brett,

I finally polished the back side of the wear plate. That's a job that I'll not do again. With a file, 220, 400, and 600 grit wet dry sandpaper, I spent several hours getting even the back side flat and smooth. A new wear plate (Sherwood #12856) can be purchased for about $15-$20. I'll add one to spare parts inventory with the impeller kit (Sherwood #09000K).

Now I think I should go rob a bank as I have no more fingerprints on my hands from the sanding.

At least I now know how to go about replacing the impeller and what parts/tools I need to carry to do the job on the water if needed.

[KevinMc]

Getting ready for the season I thought I would replace the impeller for the first time. I have the late Sherwood pump with three bolts holding the cover (on the engine side) to the pump. Have the Operator Manual open to page 15, "Changing the Raw Water Impeller." Decided to skip the steps about removing the pump and after reading the post here decided to just remove the cover. Removed the bolts without issue and I was able to pull the cover away from the engine enough to get to the impeller. Rut-row. Where is the retaining ring which holds in the impeller? Looking at the impeller in the cover it just seems to be sitting in there. Looking at the new impeller it doesn't seem to be made for a retaining clip either.

Question: Once the cover has been removed and you have access to the impeller is there a retaining clip or anything else holding in the impeller? Do you just grab the impeller with a pail of pliers and tug it out?

[KenKrawford]

Kevin, just grab the impeller and pull it out. There is no retaining clip. The face plate on the pump housing is all that holds it in.

[KevinMc]

Thanks Ken. I appreciate the info. It looks like I could just pull it out but I didn't want take a chance to make a $15 maintenance item become a three-day, one mechanic and $500 evolution.