Impeller difficulties

P

Preben_Heide

New Member
Joined
1 Dec 2002
Messages
11
Location
Aarhus, Denmark
www.ankerpladsen.dk
I've just replaced the impeller in the water pump on my Yanmar 4JH-TE diesel engine. It was extremely difficult to fit it in though I greased both the impeller wings and the pump house very well. Do you have an idea that could make this annual maintenance job a little easier for a non-mechanic?

Regards from a Danish boat owner

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if the trouble is getting the blades to go into the housing, try putting a cable tie around the blades and pulling it tight to bend the blades over (make sure they're bent in the right direction). as you push the impeller in, the edges of the housing will push the cable tie off.

should make the job straightforward.

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I went on a volvo owners training course at Volvo Watford a couple of years back. They said don't worry which way the fins are pointing when you push the impellor in because the first turn of the engine will sort them all in the proper direction anyway.

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If you used oil based grease I'd suggest you take the impeller out,discard it and fit a new one,this time lubricated with petroleum jelly.Last time I greased my impeller it wasn't long before it desintegrated.Learned my lesson,only p.jelly from now on.

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Hi,
in a flexible vane pump (i.e. jabsco, johnson etc) it doesn't matter which way round the vanes are oriented as the first turn of the key will sort that out.

Petroleum jelly is almost as bad as std. grease - the impellor is made from neoprene rubber - efficient and cost effective but usless against oils, chemicals and solids. I use volvo propshaft grease, it is expensive, but is designed not to destroy the rubber seals around the duo-prop shafts and so is fine for impellors. Alternatively, hand-cleaning soap is ideal for lubrication (not the type with pumice in though!)

The cable tie advice is great - use a fairly wide cable tie and do it up nice and tight about half-way down the impellor - if it won't slide off it can be cut off when it meets the pump housing. It really works and is a good, cheap technique that i use.

Tristan.

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The other option if you can find some is red brake grease, should be available from motor factors etc.



<hr width=100% size=1>Jim

Draco 2500
 
You could use a nitrile impeller as used for Anti-freeze they pump about 10% less
fluid however, the grease will do no harm

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The only, repeat only grease to use is a silicon or glycerine non-petroleum based lubricant/grease. Petroleum based greases will destroy the rubber. If none is available, use soapy water.

<hr width=100% size=1>Piers du Pré
http://www.dupre.co.uk
 
Thanks to you all for the good advice conc. impeller replacement and greasing. I used Volvo propshaft grease. Previous it did no harm, only good. I'll save the thread and make it a discussion topic in my yacht club.





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