Removing the impeller - HOW?

[Spirit of Glenans]

" you may have to replace the gasket so make sure you have a spare to hand".



I usually remove mine from inside the heat exchanger
Re the gasket; if you are without a spare, a tip I remember from my motorcycling days is to fix some strong brown paper, from a carrier bag or similar, over the flange and then tap gently all the way round, at an oblique angle, with a 15mm spanner. This creates an accurate impression of the flange on the paper and if you've done it properly (takes practice!) you can separate the gasket from the sheet of paper without the need for scissors.

 

[duncan99210]

If you buy a speedseal (best investment I ever made) it comes with an extractor tool - essentially a plastic screwdriver replacement - which will not damage the pump body when in use. If you decide to make a gasket following Spirit's advice, be very careful not to dent the brass pump body, which is probably less robust than his motor bike casings....

 

[NormanS]

A better way of making a brown paper (or corn-flakes packet) gasket, is to lightly smear some oil on the pump flange, press a suitable piece of paper against it, and you should then have a perfect outline of the gasket, complete with the position of the holes. Better to punch the holes before cutting out the final shape of the gasket.

 

[Burnham Bob]

when i first changed an impellor, i had some instructions that said use a pair of long nosed pliers. i did and never had any trouble. and if you grip the 'fin' close to the centre, the impellor comes out easily and undamaged.

 

[wooslehunter]

Easiest way on my boat is to take the pump off. This way, you don't have to grip anything & risk any damage. If your's is similar to mine then it's only two nuts to take the pump off. The pump shaft has a small coupler that comes out with the pump. It's just a push fit so can fall if you're not expecting it.

Now take the face plate off & push the shaft out from the back. Inside the pump there are two seals around the shaft that stay inside when the shaft is withdrawn. The impellor is held onto the shaft with a grub screw. There are two gaskets too that I cut from gasket paper every few years.

Re-fitting is a little fiddly. The shaft & coupler have slots which all need to align. Since the pump is held onto the engine with studs, the impellor needs to be correctly aligned so the pump slides over the studs. It's just fiddly & not difficult.

I could get the impellor & shaft out without removing the pmp. But, it's just as easy to remove the pump & then nothing needs to be gripped. Remember that the face plate & inside the pump make seals with the impellor. So, any scratches caused by levering or slipping with anything will reduce the pump efficiency, especially when sucking air to prime.