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 sjball |
Gasket for water pump |
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Posts: 66 07/18/07 19:58:13 |
I am planning to change the impeller on the water pump after 600 hours of use. I have not done this on the 42 Catalina. I have the 50 hp Yanmar. Is there a
gasket that needs to be replaced when putting the cover back on? Is this something you order from Catalina? Is the impeller difficult to remove?
Any suggestions would be appreciated. Steve Ball Holland Mich Hull 559 |
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lakandjc |
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Posts: 144 07/18/07 21:32:05 |
Steve: If you have the Yanmar where the waterpump faces backwards, towards the starter, consider loosening the alternator brackets so it can be rotated towards
the engine and give you some room to work. When that is done, here is what you will find:
There are four screws that hold the cover plate onto the pump. When they are removed, the plate will come off (make sure your raw water thru hull is closed and you are ready for some water to run into your engine sump) and the impeller will be exposed. There is an "O" ring gasket that fits into the pump body that the cover plate holds in place. The impeller is not held in by any other ring or clip. It can be removed, in theory, by simply pulling straight aft as it is just slid onto a splined shaft. However, getting it loose can be difficult. I have used a very small pair of plyers to grip one of the blades and pull aft to release the impeller. If the impeller and shaft were well greased when installed, it will come off with just some serious tugging. Otherwise, it can take some VERY serious tugging. Do NOT pry it out with a screwdriver, as that can damage the pumpbody and create problems. Installing the impeller will be fairly easy if you use a Yanmar part or a Jabsco #1210 impeller (I have used both and they each work fine) , which should be available at a West marine or a marine engine dealer. They have blades that can be crushed enough by hand to be slid into the pump body. Other impellers with more blades or stiffer blades may work but they can be a BEAR to fit into the pump body and later remove. Clean and grease (I have used Lewmar winch grease) the back of the pump body, the splined shaft, the surfaces of the impeller ends, and the round parts of the blade edges. Crush the blades on one end by wrapping your thumb and forefinger around the impeller and rotate it into the pump body until each blade is inside the entrance of the body. Then, as you push the impeller onto the shaft, recall that the inside of the pump body is NOT a circle but has a flattened side, and therefore the impeller will try to go in at an angle. Work to correct that so the impeller slides onto the shaft as easily as possible. Finally, the impeller will fit entirely into the body and the blades ends will be flush with the face of the body. Clean and grease the slot the "O" ring fits into and the ring, install the ring, clean and grease the plate, put a smidge of grease on the screws, and replace them, tightening each one little by little so they have a balanced load. If the plate is scored, consider replacing it or see below. All of this will A LOT easier if you replace the original plate and screws with a Speed Seal which you can buy on the internet. The Speed Seal uses knurled screws you can unscrew by hand and a plate that slips off the bottom two screws so they don't have to be removed, just loosened. This alone is worth the price of this beautifully made part. If you ever have to replace the impeller in a hurry or in a serious sea condition, you will be VERY glad you have the Speed Seal. I think I have gotten most of that right (and someone please correct me if I didn't) and hope it helps. And DON'T FORGET TO REOPEN THE RAW WATER like some of us may have at 4 AM in a six foot swell. Good luck ... James White Star #450 Puerto Vallarta |
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tomcharron2 |
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Posts: 48 07/20/07 21:16:20 |
Steve:
Here is a posting done by me last year on the subject.. I suggest you search using the word 'impeller" you will find a wealth of info already posted on this forum Good luck on your water pump work. Tom Charron MiVida C42 #631 ======================================= IMPELLER REPLACEMENT PAINS C42 #631 (1999) 50 hp Yanmar Have you EVER replaced your engine cooling sea water pump impeller???? If so/If not...... READ FURTHER.....here are some of my thoughts on the matter. In prep for another cruise from SF Bay to So Cal this year and after 982 hours on my C42 #631 Engine...... I felt it very reasonable to replace the IMPELLER on my Yanmar 50. After all the prudent practice is to replace your impeller each season....mine had been functioning without hesitation for almost seven years!!!! Really this was the year i should do the replacement.... HERE IS MY EXPERIENCE: Changing this rubber/bronze unit WHILE in port, is MUCH WISER than replacing it at SEA...Right???? After running from SF to SanDiego and return with out problem last season, (on a 10 week cruise), I felt it imperative to replace the impeller (in for 7 years and almost 1000 hours of use!)...for this year's repeat cruise down and up the California Coast. I checked the discussion forum and the web site for our C42 group....but found little (if any) 'BELIEVABLE' info on the process. Having changed the impeller on my Catalina 30 a few times without problem (and numerous hours experience rebuilding diesel/and/gas engines) I proceeded to perform the necessary work on the shaft-driven Sea Water Pump unit on my Yanmar 50 hp engine...!!!! It seemed simple enough....just remove the impeller cover plate from the aft section of the sea water pump on the port forward side of the diesel engine and pull the impeller and replace. (Please note......IF THIS CAN NOT BE DONE I/YOU MUST MOVE THE PORT FORWARD MOTOR MOUNT TO TAKE THE PUMP UNIT OUT!!!!!...as the bolts for the pump impinge on the motor mounts on the port forward side of the engine)....NOT A FUN PROCESS TO EXECUTE!!!....Anyone experince this situation???? Oh those damn design engineers who never have to service the results of their labors!!!! They all should have to live in an engine compartment for at least one week!!!! Seemed (to me) easier to remove the pump impeller inspection plate and pull the impeller aft for removal and replacement...... Well this is not as easy as commonly postulated (see C42 web site tech info). Yes it is easy to remove the backing plate on this pump. Yes it seems easy that one should easily pull the impeller aft and remove/replace with a new impller easily. Well....not so easy and simple, there are no 'puller notches, holes, grooves etc on the impeller......(OH THOSE DAMN Design ENGINEERS....they should have to perform maintainance work on all units they design...on the boat...in place where the engine is used to do real work on a boat....If they can't repair/replace items without 'pain' then they have to redesign and not receive pay until same is produced.... we should have 'ergonomic maintainance standards' for mechanical designers to recieve a paycheck...!!!!). For my experience at this task......the impeller remained nicely nested, ....rather....'glued',..... in the pump housing....refusing to move out aft until I removed the sea water supply line and created a tool (from a flat long shaft screw driver...bent appropriately to leverage the old impeller out).... Took about 2 hours of careful work (and tool making tasks) to move the impeller aft...along with some help from a pair of 'stubby flat-head screw drivers' and a 'short handled...needlenosed' vice grips I carefully placed on the impeller vanes with traction aft..... EUREKA I removed the ORIGINAL impeller and found it to be in excellent shape...WITH 982 HOURS OF USE!!!! No wear, cracks, tears, abrasions, no lost vanes etc....Testament to the fact that I never had 'run her dry' (I think!!!) ....she had never been overheated!!! Aynway....I replaced this intact original impeller (with 982 hours of continuous revolutions on her) with a NEW IMPELLER!!!! So with the new impeller from Yanmar....I replaced all seals/gaskets (2) (on on the shaft, forward, and the gasket facing the plate/cover) along with a new Impeller..... and she runs well....!!! LESSION I HAVE INCORPORATED IN MY FUNCIONAL MEMORY BANK!!!..... 1.) Changing the impeller on the Yanmar 50 in my 1999 C42 took about 3.5 hours. 2.) Those C42 owners of poor mechanical ability/experience should think about what they are up aginst. (creating tools to do the job etc). 3.) I would not want to change this impeller (FOR THE FIRST TIME) while at sea!!!!!! (SECOND TIME.with custom tools would be better!!!!), 4.) The original impeller (982 hours of engine time) was IN GREAT SHAPE and really DID NOT NEED REPLACEMENT!!!!!!!!!!!.....WAS THIS A 'testament' to what I think is proper strainer of sea water, never starting/running the engine with the sea-water thru-hull closed, and meticulous monitoring of engine temps at all times!?? OR JUST PLAIN LUCK ON MY PART!!! Mabe it was just a beefy constructed and well designed Impeller....even if it is a BITCH to replace!!!! 5.) NOW I know what I am up against if, (God Forbid) , AND COULD DO IT!!!, since I have done it in port.........IF I have to do it at SEA!!!! So much so for the letter regarding Impeller replacement from Yanmar posted on the C42 web site!!!!....as you can decipher....my experience is much different! At least it was done by me for the cost of the parts....!!!! Good luck when your time comes to perform this maintainance task.... MAY IT BE DONE IN PORT ...FIRST TIME....NOT AT SEA ON THE FIRST ATTEMPT! (motto...."DO IT at HOME, FIRST!!!!....just like MOTHER TOLD you!!"....but IN ADDITION SHE TOLD ME ALSO TO make sure I always have a spare impeller, alternator belt, fuel filter(s) ETC, ETC, etc, etc while at sea!!!!) Your thoughts, experience on impeller replacement problems, and comments appreciated. Tom Charron C42 #631 MiVida Alameda, California tomcharron@alamedanet.net
Last Edited By: tomcharron2 07/21/07 21:24:06.
Edited 1 time.
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SteveInMD |
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Posts: 38 07/21/07 05:56:52 |
I just discovered that the water seal behind the impeller is leaking. It looks to me like the motor will have to be jacked up and the motor mount moved so the
pump can be removed. A mechanic looked at it and agreed. He said it would probably be $400 to $500 to remove the pump, rebuild it, and replace it. Does this
seem right?
For those of you curious about how long an impeller will last on one of these pumps, the previous owner told me the impeller now has over 1,200 hours in it, and it's still fine. #446 Swim Lessons |
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lakandjc |
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Posts: 144 07/21/07 10:07:52 |
Steve: RE impeller life, I lost one after 200 hours but have 400+ on this one and it's going fine. I met a cruiser in Mexico this year who replaces his on
each oil change, and know others who replace theirs at the beginning of each season. I have a friend in California who has approx 3000 hours on a Yanmar 44 who
has NEVER replaced his.
It has to do with luck and what you may pick up. Sand from motoring off a sandbar, for instance, or a piece of plastic or seaweed, may damage the impeller or cause it to run dry. As Tom says above, owners should have the parts, the tools, and the skill to be able to replace this part at sea. It can save your boat. And get the Speed Seal. If you only use it once, it will pay for itself. James White Star #450 Puerto Vallarta |
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