Fitting a paper gasket to Jabsco Raw Water Pump?

[Anonymous]

My first reaction is that impellor technology is so mature that I question whether anything inherently unsound would leave the factory - but these things do happen when all the experienced designers leave/are fired/retire leaving the design department staffed by people who took GCSEs rather than A levels /forums/images/graemlins/wink.gif

The torque on the shaft of the impellor must be a function of the load. Could it be that the seacocks and piping are undersized and a much higher load than they'd been designed for? Maybe you could get the pump curves from Jabsco or Johnson and see if that could be the case?

 

[Richard10002]

Bit the bullet and opened it up again last night - gasket and new cover and silicon grease to hand, (dont use vaseline said the impeller instructions).

Opened up, checked the impeller was not proud, which it wasnt, but i did notice a nick at the bottom of one of the blades, so decided to put another new one in.

Wasnt sure which way round the gasket goes, and couldnt see a difference in the shape either way - decided it probably didnt matter.

Glycerined the new impeller, inside of pump body, new seal, and mating faces.

Impeller went in much easier this time - probably all the practice i've had!

Stuck gasket onto plate.... put one screw through, and got it in place. Wasnt convinced that the holes in the gasket were exactly aligned, but hoped that the screws would manouevre it into place.... I'm pretty sure it worked.

Switched engine on ... dashed to back of boat to check for water ...... the usual nervy 10 or 20 seconds.... almost ready to dash back to the cockpit to turn off...... splash splash splash, phew! Watched it for a while, then dash back to the aft cabin to check for leaks .... all fine.

Did 7 miles or so at 2000 revs today, and still all fine.

So there you go - getting the impeller in is a bit fiddly, but havent resorted to the cable tie yet - getting the gasket lined up, a bit fiddly, but managed it OK.

This on a boat where the water pump is really easy to get at.

Hope this thread is useful to others in the future.

Thanks to all for the help as usual

Richard

 

[Anonymous]

Glad to hear that you are finally there! Phew!

The type of grease you use is an environmental issue, hence glycerine. Lots of folks use washing up liquid, I use KY Jelly. You don't want to glycerine the whole area, only the impellor otherwise you will be tending to drop all the bits! The point of the glycerine is to help the impellor push back into the pump housing. Sometimes you have to drift the impellor in carefully with a soft hammer, I have to use a large clamp (like a huge G clamp) and screw it gently home as I cannot get a hammer in there.

Since you nicked the last impeller you need to address this whole issue or it might happen again and will certainly result in premature failure, even almost instant failure, I suspect. I can't think how you managed to nick an impeller getting it in...getting it out, yes, but not in. How did that come about? Before you put the cover on you need to feel confident that the new impellor is in A1 condition.

Some gaskets are handed up/down and rotationally. I suppose others might not, but all mine have been. I've never had a gasket that did not line up perfectly with the cover. But if it isn't leaking it will be fine.

I strongly suggest that as soon as you get to you winter berth you order a Speedseal. http://www.speedseal.com/ Alex is the guy's name and he is both knowledgeable and helpful. With a Speedseal you will get a new cover plate with O ring (so you won't need paper gaskets ever again) and instead of screws with screwdriver heads you get large knurled knobs so you don't need to use any tools to get the cover off or put it on. Speedseal also comes with a simple puller - Alex plays down the efficacy of the puller, I suspect that it works better in some installations than others, but then again, it is supplied 'free'.

 

[rogerthebodger]

One of the things I have done with my raw water punps is to replace the screws with studs in the pump body so the gasket and end plate locates on the studs and use wing nuts to clamp the end plate on.

 

[BlueSkyNick]

Sorry, only just got around to reading this - David seems to have given you lots of good advice so nothing to add. I bought a Speedseal as soon as we bought the boat and fitted it first service. No drips from Almerimar to Lymington - and we motored a lot - if you exclude the 4inches of seawater under the engine due to the exhaust mixer box blowing out a drain plug !!