Fitting a paper gasket to Jabsco Raw Water Pump?

Richard10002

Richard10002

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Skip to THE REASON FOR THE POST if not bothered about the events leading up to it:

Heard a change in the engine note last night, almost like it missed a beat - which it hasnt done in a few thousand miles, and many hours at anchor - turned it off within seconds and no damage done. Initially worried sick at the thought of being scalped by an Italian yard, but calmed down and thought it through over a cup of coffee and a few fags.

Checked the oil - fine, but topped it up. Checked the raw water inlet filter - plastic bag!!! (thought it was a jellyfish at first), plus a fair bit of weed. So I'll be checking that more often.

Opened up the pump and, whilst the impeller looked OK, decided better safe than sorry and replaced it, (which is easier said than done - how do you get them out without risk of damage?). The old one is fine, (new in June), so I'll keep it as a 3rd reserve.

Having glycerined it all up, and replaced the cover, but not the gasket, there is the tiniest leak from the bottom - a tiny drip avery 30 seconds or so.

THE REASON FOR THE POST:

Somewhere else today, someone said that replacing the cover with a Speedseal meant never having to deal with the awkward paper gasket ever again.

I've got a gasket, so what is awkward about replacing it, and any tips?

many Thanks

Richard
 
i bought an impeller remover,its a small 2 leg puller,brilliant thing.it was about 17 pounds if i rember right which is quite a lot to have sitting above the pump ,but changing an impellor at 3 in the morning,worth its weight in gold.
i have got a speedseal fitted which is excellent,i bought it because fitting 4 large knurled bolts seemed alot easier than 6 small screws, not sure what the paper gasket problem is as it would seem to me no better or worse than the thin o ring on the speedseal,ie both need grease to hold them in place.
glad all is ok you must nearly be in malta now i guess
 
[ QUOTE ]
but changing an impellor at 3 in the morning,worth its weight in gold.

glad all is ok you must nearly be in malta now i guess

[/ QUOTE ]

That's what time I got finished, (4am here). Toyed with putting it off till the morning, but you never know what the weather is going to throw at you, so I got on with it, (slowly).

Biding my time in Taormina, but heading for a couple of days in Ripost marina next Mon/Tues, then on to Syracusa next Wed. weather permitting. I'll stay there for a while, and can always hole up in Mgarr for a while, if nothing is available in Malta.

Thanks for asking

Richard
 
I am another happy user of the Speedseal. To get the impeller out, however, I use a cheap pair of slip-jaw pliars, also known as - water pump pliers. /forums/images/graemlins/smile.gif
I cannot understand why these never seem to be recommended in maintenance articles when they are so easy to use - far simpler than "carefully position two screwdrivers" etc.
 
That's the beast! Mine is Draper, has less fancy handles, and was probably a bit cheaper. As long as the jaw thickness is less than the distance between impeller splines, and there are an even number of splines, then the centre of the impeller can just be grabbed across its diameter and hauled out. No risk of anything slipping and causing scores.
 
Never use a gasket on mine, just a smear of seacock grease around the mating surfaces. never had any leaks.
 
As long as the faces of the impellor housing and the cover are in good nick and the gasket is ok.
A bit if glycerine or grease will normally do the job.

Yep the Speedseal derivatives are handy.
There are the , "Knurled nut types" and the "Allen key types".
Both easier to service and remove than the srewdriver type covers.
Some pump covers have an "O" ring as a seal and some the paper gasket.

I have two new replacement impellors on the Boat.
"Volvo" but not really.
Patterns. I notice there is a new paper gaskett with both of them however.

Impellor removel.
Always done it gently with "Take two Screwdrivers" method.
Painstacking but OK.
Agree the puller would be good.
But not essentcial.
Depends on access to the pump area.
Removed and replaced one last week.
Cripes! NO ROOM FOR THE SCREWY . Or an impellor removing tool.
What a gig.
But that's boats
 
While we are on the subject of impellers - Has anyone with a Yanmar 3 Fresh water managed to reverse the stupid arrangement where the water pump and therefore the impeller cap is fitted facing the engine block. This means that the whole pump unit has to be removed to replace the impeller. Spoke to Yanmar and was told that it wasn't a problem as it only took a minute or to to do this -- Yea right!especially in an emergency. (Apologies for pinching the thread)
 
i seem to rember an article aboout modfying a pair of long nose pliers to remove impellors.
if you put a small right angle bend on the tips of the pliers first.
then heat the the arms and bend them in so that when the handles say have an inch of gap at the top the right angle tips are just touching.
the crucial bits are that the tips are long enough to catch under the impellor so maybe 6mm or so
the gripping bit is longer than the body of the impellor and after being bent end up when nearly closed running somwhere nr paralell to the body of the impellor.
it may be better to weld a stub on the ends and grind/file it down to suit,depends on the pliers you start of with
 
Richard, these pumps can cause terrible trouble if there are leaks or if the paper gasket is not in place. The thickness of the gasket is designed to provide the correct internal clearance - too much and you get cavitation or air getting in and too little and it binds up. In time, impellor covers wear, in which case turn them over and use the other side - they are reversible.

If the job isn't done just right then you can find the cooling water runs intermittently. If there is a leak - even a few drips - you need to sort it before going to sea.

They are a pain in the backside, which is what you didn't want to hear.

Oh, as for getting the impellor out, if you buy a speedseal they include a free puller. You can also buy a Jabsco puller but you'd probably need to wait until the credit crisis is over /forums/images/graemlins/wink.gif

Summary:- Try reversing the cover if there is undue scoring and if you haven't got a spare gasket (you can't, it seems, buy spares /forums/images/graemlins/confused.gif) then leave the old one in and smear grease over, but don't leave it dripping, if that fails.
 
David et al,

thanks for all of that - I've actually got a kit which includes gasket, new cover, screws, and stuff I dont recognise, so no problem in terms of bits.

I am reasonably sure the issue is the gasket. 2 new impellers ave been fitted without replacing the gasket, and it looks a bit iffy. At 4am, I thought I'd give it a go, but I obviously need to sort it.

I was mainly concerned about the problems with fitting the gasket - i can imagine it sliding about whilst manouevering it into position, so getting it to stay in position with the holes in the right place might be difficult.

As nobody has commented on this, other than to say grease it to make it stick, I'll crack on when it gets a bit cooler.

As a matter of interest, the existing cover has jabsco inf. engraved/stamped on the other side, so not sure if it is a good idea to reverse it.

Many Thanks again

Richard
 
we have used the stamped/ engraved side, about 20 times (2x main + 2 gen +previous boat)just sand off the paint first.the letters dont seem to matter


was shown by mercedes benz chief engineer in the 70s (he was a scots man so knew where savings could be made)
 
Richard, The engraved side should be fine but since you have a new kit and you are working under duress in the heat, during the cruising season, then I would use the new kit and keep the old bits to sort out later, maybe when you change an impellor in the winter during planned maintenance, when you have time and comfort. Comfort being relative with impellors - depends on the boat, actually, some are a doddle and some are a real pig. No Big Nick or M44 owner has jumped in yet so I'll bash on....

Obviously you will use the new cover right side up. The other bits might be a new water seal which you seldom need but is VERY EXPENSIVE so don't lose it! It goes inside the pump assembly...look in your book on maintaining diesel engines and it will explain all (you do have a book> /forums/images/graemlins/wink.gif). Assuming that your impellor is properly home (feel with a finger round the very edge of the housing and be sure that the impellor is not proud even by a fraction. It MUST feel level or a few thou in.

Feel around the edge carefully to make sure that there are no bits of old gasket or scoring (which might be the case if someone has been clumsy when removing an impellor in the past). If you have got scoring then you will need to use a silicone gasket compound on both sides of the gasket and let it set for some hours before using.

Now, offer the gasket up to the cover and make sure you have it the right way round and also the right way up. Maybe make a mark with a soft pencil if you need to remember which way it goes. Put a tiny smear of grease on the smooth (inside) of the cover plate and put the gasket on that...this should hold the gasket in place. Now, remembering how Twizzle coped with these things, simply pop a screw in the hole of the cover that will be uppermost, and try to get that in a few turns until the cover is dangling. Now get a second screw and try to get that into the bottom hole, ensuring that the gasket is still stuck with the grease to the cover, and screw that it, not tight, but so the cover is now very slightly loose. Put the remaining screws in and tighten opposites as if you were changing a car wheel.

Now start the engine and check very carefully that there are no leaks. There must be NONE or the pump will probably stop pumping just when you need it most.
 
Exactly!

I removed and replaced the impellor last winter on my Beta engine using these. It's a piece of pi$$ on this engine as it's right at the front facing me as soon as I remove the steps!
 
No problems fitting the paper gasket provided you clean the mating surfaces and check no burrs have been raised when stripping the pump down or removing the impellor. Clean any
burrs off with a fine file, lightly grease the gasket, replace the cover and gradually nip the screws up from opposite sides not 'aroundthe clock'. Incidentally an impellor that has overheated may break up in use and bits of rubber block the engine's waterways.
 
Hi there, for many years if we have needed to replace paper gaskets on various ships we've used home-made ones cut from chart paper, again with a smear of grease to hold them in place. (Yet another disadvantage of electronic charts! /forums/images/graemlins/laugh.gif!) If you have half decent access it can be easier to stick the gasket to the cover plate and put a couple of the screws through plate and gasket before placing it on the pump.
Also we often reversed the cover plate if badly worn, the engraving is too fine to have much of an adverse effect. Don't forget that the cover plate screws are normally arranged asymmetrically on Jabsco pumps. Also be very careful of damaging the sealing face if using the 2 screwdriver method of impeller removal...
My new generator engines have quite large impellers, about 5-6 inches long and 4 across, these are proving to be fairly unreliable, my personal opinion is that they are putting too much of a bending force on the splined shaft as they compress the vanes on the cam-plate. Time for a redesign maybe?
 
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