Impeller change?

I have been looking at boats for sale on this site and many descriptions say "the impeller was changed every year". I assume this is the impeller for the water pump, so is it necessary to change this on a regular basis? How much do they cost and are they readily available? Is it a big job or can most people do it? Thanks

BTW mines '75 with a 351

Warpman,
Welcome to the site! The impeller is one of the easiest things to do and should be part of routine maintenance every year depending on how many hours you put on your boat each year. It's easy and one of the things you don't want to fail.

Loosen the belt that goes to the water pump (prob through alternator on a 351). Then take out the two bolts that attach the pump to the block. It's a good idea to mark which way is up on the pump so you don't re-install backward (take it from a guy w/first hand experience). Take the pump apart carefully (prob three bolts). There will be a small gasket in between the two halves. Take it out (the new one should come with the impeller) and replace. Look to see which way the tines are bent on the old impeller and install the new one so the tines bend in the same direction. You may need to clean the edges of the two halves of the pump so it matches up well. Put it back together being careful not to strip the bolts that hold the pump together. Reinstall pump on block--right side up! Tighten the belt. Wvalla!

There may be a couple secrets to this that I'm leaving out, but it's pretty straight forward. I'm not a mechanic and I can do this. Go for it!

The Dude wrote: Warpman, Welcome to the site! The impeller is one of the easiest things to do and should be part of routine maintenance every year depending on how many hours you put on your boat each year. It's easy and one of the things you don't want to fail. Loosen the belt that goes to the water pump (prob through alternator on a 351). Then take out the two bolts that attach the pump to the block. It's a good idea to mark which way is up on the pump so you don't re-install backward (take it from a guy w/first hand experience). Take the pump apart carefully (prob three bolts). There will be a small gasket in between the two halves. Take it out (the new one should come with the impeller) and replace. Look to see which way the tines are bent on the old impeller and install the new one so the tines bend in the same direction. You may need to clean the edges of the two halves of the pump so it matches up well. Put it back together being careful not to strip the bolts that hold the pump together. Reinstall pump on block--right side up! Tighten the belt. Wvalla! There may be a couple secrets to this that I'm leaving out, but it's pretty straight forward. I'm not a mechanic and I can do this. Go for it!

Thanks for the reply, that doesn't sound hard at all.
Does anyone know what typically causes an impeller to fail? And what indicates that it has failed while operating the boat? High Engine temp?

I used this page when changing mine, and found it to be good:
Aqua Skier Impeller Change

Actually, your boat essentially has two water pumps. The circulation pump (which is just the same as a car's water pump) and the raw water pump. The impeller that everyone is talking about is in the raw water pump. Actually, it's not attached directly to the block, it's attached to a bracket.

I found that a set of SAE "GearWrench" Wrenches was pretty useful for this. Although, I only needed one or two from the set, it made it a little easier than a socket and ratchet or traditional combo wrench.

I have nevr had any problems yet. I follow every 100hrs or 2 years. I hope this helps.

I believe they're all the same for PCM Sherwood:
Impeller Kit

If you have the original right hand turning PCM engine your pump should be mounted like this,with the cam screw facing out-


If the engine has been replaced with a left hand turning one,like whats in a car the screw faces in-

Gary, in the top photo (right hand drive) does the pulley turn clockwise or counter clockwise?
Thanks Tom

Gary S,
Curious to know if you have rebuilt this pump? I have a Sherwood 12328 off an '82 with a 351 that fried out the bearings. I was able to disassemble the pump, with some choice words, and now have two empty housing halves and a marred impeller shaft from grinding those two sets of bearings. Are you aware of rebuild kits that would cover all the internal parts as well as the shaft? I can not tell if the shaft was pressed or threaded into the pulley as well. Thanks for any ideas or directions.
Rich

Thank you for the heads up. I have two brand new impellers thinking my problem was a toasted impeller and ordered an extra as a just incase spare. I've completely torn down this pump and now vacillating between rebuilding, buying a rebuilt or purchasing a newer version based upon availability. There is some sticker shock with the new pumps.
Thanks,

Could the shaft be saved with a speedi-sleeve?

Gary, I can only assume it's the 21 based on discussions but not 100%. A G20? There is one issue that has me wondering if I really screwed up. While disassembling the pump I had to remove a part from the housing that resembles a bunt cake pan. It was, past tense, a brass "cup" and I have not seen one schematic showing this part. From memory the spring/tension seal sat in this cup and created a seal to the underside of the wear plate, my words, opposite the impeller housing. Do you know if this part is a factory install?
Thank you,
Rich

So it does exist! I figured so but never saw a diagrahm with the seal. What was your rebuild time once all parts were gathered together? Also, where did you purchase the seal? I see you shopped the bearing and some other parts off eBay.
Thanks

Now would be a good time for you to come forward with pictures, like Gary has done.

Hollywood,
I'll post this evening so you can see my old parts. Which of these icons lets me post pics?
Thanks