Impeller question

[colemj]

Originally Posted by lancelot9898

Note on your photo that some of those vanes are pointing in the opposite direction.

This isn't a problem. When the engine stops, it often rocks back a little bit and the vanes turn. In fact, there is no reason to be concerned with impeller positioning when you install a new one - slap it in and the first 1/4 turn upon starting will align all the vanes properly.

Mark

[NOLA_sailing]

Originally Posted by Lake-Effect

Just furthering my education: are you gents recommending impeller replacement because of something you see in the photo, or more because it's a new (to the owner) boat and the age of the impellor is uncertain?

Thanks

With the boat being new to you is enough incentive to change. Same goes for fuel filters and engine oil/filter. As is the usual qualifier on here, I know from experience. It's not fun spending hours picking pieces of rubber out of a heat exchanger. I'm just glad it was November and not August.

[Lake-Effect]

Thanks all for the explanations. Note that Stevelack is the OP and the one with the westerbeke... I'm just here vacuuming up knowledge.

(Though I have helped a friend pick bits of impeller out of a 4-cyl Volvo in a motorboat)

[sparrowhawk1]

The easiest way I know for replacing an impeller is to put it in a hose clamp tighten the clamp up till its the same size or just smaller than the opening, hold the hose clamp tight against opening and just push impeller out from the hose clamp right into the opening.

[tartansail]

Is it OK to insert a bit of a water pump">raw water pump rant here? I have a Universal engine with a Sherwood raw water pump. How can anyone take such a profoundly simple piece of kit and turn it into a sadistic attack demon?

First, the bolts. Why on earth do the 7/16" heads have to be on the back of the pump? There is clearance on both sides. (Though not enough for a ratchet in back. Only a hex and room for 1/6 rotation.) The only possible explanation is that the designer wanted my knuckles to suffer as a reminder that impeller changes are too important to be bloodless.

Second, the half moon shaped key. Is there actually a reason to make the key this shape and so prone to fall out other than to demonstrate that the bilge under the engine needs cleaning? And, once proven, does it need to fall out again. And again? OK, I cleaned.

Third, the bolts again. Stainless bolts into a bronze housing. No way those bolts are ever going to get cross-threaded. Especially when you're wrenching without visibility because the bolts are set up in back. (See one.) The only good thing is that I can use the excuse to use a through bolt with a nut and eliminate the challenges of wrenching from the back.

Oh, right. This is about getting the impeller into the housing. Lots of good suggestions that aren't Sherwood specific, but do eliminate one of the sources of bad language. [/rant]

[Capt Phil]

Just a quick word of advice... in addition to the fine suggestions above, I just changed out the impeller on a friends boat that had been over heating. On removing the water pump, the impeller had virtually NO vanes left it had been in for so long so I replaced it.
The first question you have to ask is where did the rubber vanes go?
I broke the intake hose away from the sea strainer and put the end in a bucket, fired up the engine and waited for water to flow out the aft exhaust... NADA!
The next step was to remove the heat exchanger the raw water cools. Before doing that, I cranked the engine, a Yanmar, up to about 2200 RPM and blew a piece of rubber vane out of the heat exchanger about 5 feet!
This was a lucky fix! The engine now runs cool, heat exchanger has cleared itself and the new owner is happy.
Had the heat exchanger not cleared out the piece of rubber under load, it would gave to be removed and taken to a shop to be cleared out. Cheers, Phil

[Stevelack]

The engine is a Westerbeke 36 hp, but it has been rebuilt and the impeller pump is a Jabsco pump. Hoping the survey will point me in the right direction as far as immediate needs and routine updates and maintenance. Been reading a lot of Don Casey and Nigel Calder. Thanks for all the advice!