Changing the impeller on a 1981 Cape Dory 30 ft cutter MD7

[Richard G. Abbinanti]

looking for help. I asked my boat yard to replace the impeller on my 81 cutter. The yard said that it was a big job and I should replace the water pump at the same time. That the impeller was in the back of the boat and very hard to get to. Is this so? Is it a job I can do?
Thank you
Richard Abbinanti

[bottomscraper]

You can look at the owners manual right here on the CDSOA web site. Use the link below. I don't have a CD30 or an MD7 so others will need to chime in on how hard a job this is. It does appear to be at the back of the engine.

http://www.capedory.org/manuals/VolvoMD7AIB.pdf

[Steve Laume]

I have the Universal engine with the impeller in the front. It is not a big job to change the impeller. Yours might be hard to get at but I can't imagine it would be that hard to change. I have changed impellers several times in the few years I have owned my boat. Once was because it would not work as it had taken a set in the cold of a January sail. I would definitely want to know how to deal with this myself on any boat I owned. I did replace my water pump this year but only because I knew the shaft seal had failed and had priced out a rebuild kit. In my mind, the impeller replacement should be routine and the pump only when it fails. Maybe replacing a 25 year old pump would be a good preventative measure. So the yard would have given you good advice. On the other side of the coin is that it might be time to replace the whole engine if that is your line of reasoning. No matter what, I would learn to replace my own impeller. Best of luck, Steve.

[Neil Gordon]

The water pump is in the back and it's awkward to get to. But that's no reason to replace the water pump. If thet're telling you it would be easier to replace the impellor by removing the pumpi'd still be wary), changing the impellor and then reinstalling the pump, maybe (but I'd buy that.

There are all sorts of hard to get to service spots... somehow my mechanic finds a way.

[Stan W.]

Assuming raw water cooling, there is one pump and it is in the back of the engine. But, I thought CD 30 motors were installed backwards with a v-drive? In that the case, the pump shouldn't be too hard to get at. It gets slightly more complicated if you have a heat exchanger and a second pump.

[rtbates]

I belive it would be a bear to change the impeller. Getting the old one out can be a bear and getting all the vanes leaning in the right direction at the same time as the new one is slipped into the housing can be a challenge. I say this after changing my 1GM impeller while sitting down looking straight at the pump and it's an easy reach! I would highly recommend going with a SPEEDSEAL cover. How old is the pump? Is it leaking? You don't want to put a new impeller into a worn out leaking pump for obvious reasons, especially on that motor. Changing the belts is a job also. Do you know any really good, really SMALL mechanics, preferably with LONG arms???

[bottomscraper]

I use glycerine as a lubricant to make putting the impeller in easier. It also provides initial lubrication. Melissa buys it for her soap making hobby and I "borrow" a little. Speedseal is a good product!

Speedseal Web Site

[Carter Brey]

The MD7A is notorious for difficult access to the water pump for an impeller swap. As Randy, says, it's an excellent candidate for a Speedseal, especially since this is a standard annual maintenance chore. In the absence of symptoms, I don't see why that should justify the installation of an entire new pump.

Don't worry about the orientation of the impeller vanes; they orient themselves correctly as soon as the engine turns over.

The suggestion of glycerine as a lubricant is a good one; you can also use silicone spray or lithium spray. Use something so that the poor little thing doesn't burn itself out before getting a prime.

Carter Brey
Sabre 28 Mk II #532 "Delphine"
City Island, NY

[Michael Abramson]

I have a CD Intrepid 9M and it uses the MD7A. There is plenty of clearance to access it, and the cover comes off with 4-6 small screws. Changing the impeller itself is dead simple, I think anyone could do with with even common homeowner tools. Aligning the vanes is a piece of cake and could be done with one hand, this impeller is only about 1.5" diameter.

I don't know what the clearance issues are in the CD30 installation, but I'm sure that is the main constraint for doing this job. Since the CD30 installation has the MD7A backwards compared to a standard installation, that puts the pump at the front. If you have room to get an arm down in there, I think you could do the job. The only caveat is if there is a lot of green corrosion on the pump, then the little screws can break off before they unscrew and then you will have a challenge. Changing the whole pump out will be a $500 job at a yard, so if it was my boat, I'd certainly try to do it myself. Then it will be about $30 or so for an impeller, and Jabsco and others offer one that will fit.

[Richard G. Abbinanti]

I thank you all for your comments and getting back to me.
Richard

[Mitch F]

On our CD 30, and most with the MD7A I think, the engine is installed backwards with a V-drive so the back of the engine is what you are looking at when you remove the companionway steps. The only hard part about accessing the water pump is the fact that it is buried under the exhaust can with almost no clearance to get a screwdriver on the screws to remove the impeller cover. I recommend picking up some of those cheap screwdrivers with a 90* bend in them. Removing the cover is still a nuisance of a job but its not difficult.

[Derek Matheson]

I replaced the impeller with Globe Blue 1112 from Redden at $16.36. This is higher quality material and advertised to run dry without burning up and shredding. Probably made from cast urethane, definitely not rubber.

http://www.globerubberworks.com/nav.php ... s_impeller

It was an easy job, but then again I am skinny with long arms.