water pump rebuild

[mat_ryall]

Hi,

I have stripped the pump down from my 1990 5hp Evinrude (same as 6hp) as it did not seem to be pumping very well. There are two gaskets either side of a metal plate which seals the water pump housing to the top of the gear case. I think the reason for the poor water flow may have been due to the failure of one of these gaskets rather than the impeller (the impeller that I removed looks O.K; I will install a new one anyway).

On reassembling the pump should I use some gasket sealant along with the gaskets or should the gaskets be O.K on there own?

Cheers, Mat

 

[Vic.S]

Re: water pump rebuild

Yes fit new impeller. they get tired with being scrunched up inside the housing after a few years,

I have never used sealant on those gaskets but just enough, no more, to stick them in place will do no harm. You dont want excess sealant squeezing into the pump! I dont think the bottom one is critical anyway. Top one has to make a seal between the impeller housing and the plate

Connect a hose to the water tube and make sure you can get a good flow of water through the engine. Grommet at the top of the water tube is the major problem with my '84 6 hp.

 

[mat_ryall]

Re: water pump rebuild

Thanks for the info, good tip regarding water flow through engine. I guess that will tell me if the cooling channels are corroded and blocked up. If they are, is there anything I can do about it?

When you say the grommet at the top of the water tube do you mean the little rubber insert ontop of the water pump housing where the water tube from the engine fits into?

cheers, Mat

 

[Vic.S]

Re: water pump rebuild

Yes the water channels can become blocked with corrosion and scale. The channels around the cylinder head are particularly vulnerable although as yet I have had no problems. Maybe because my engine remains vertical and therefore drains. If not too bad maybe a descaler run through from time to time would help but if they become totally choked then it's head off and dig them out I think.

The grommet I refer to is the one at the top of the water tube, not the one at the bottom. Yours may be slightly different but the trouble I have is that corrosion of the inner exhaust tube, in which it sits, squeezes the grommet over the top of the tube until it completely blocks off the water flow! If I poke a stout wire up the water tube and it hits something rubbery at the top I know I have trouble up there but if it hits hard metal I know it's gone right through without problems. Power head off to sort it out of course when necessary.

 

[krogie]

Re: water pump rebuild

on some of the smaller class motors i have seen blockages at the same spot you were talking about. usually water scale or some sort of calcium buildup.i still have not figured out the perfect tool for getting in there and giving it a good cleaning.

 

[mat_ryall]

Re: water pump rebuild

Thanks for all the info guys, I will check the flow of water through the engine tonight. I ran the engine when I first got it a couple of weeks ago, there was water coming out of the pipe but not much, certainly not a steady stream. That lead me to strip the pump and change the impeller. I probably should have checked that the problem was not a blockage further up first, still probably no harm in changing the impeller anyway. Also I'm enjoying working on the engine! The big long bolt that connects the gearcase, mid section and upper section together was a real ***** though.

I have ordered a manual from crowley marine, there didn't seem to be anywhere in the U.K that sold them so I may have to wait a while before it arrives. In the meantime thanks again for all the advice, excellent forum.

 

[Vic.S]

Re: water pump rebuild

In the UK?

www.Willsmarine.co.uk and www.outboards-direct.co.uk useful names for mail order spares

www.YBW.com/forums for the best boating forums in the UK

 

[mat_ryall]

Re: water pump rebuild

Frome, Somerset.

I've used Willsmarine for the parts I've bought so far, he seems pretty helpful. My biggest problem has been finding the correct parts list/diagram for my engine. It's a BE5DRLESR, which would make it a 5hp 1990. All the U.S sites that have exploded diagrams with parts lists don't have this model. I'm currently using the 6hp diagram, i think it's pretty similar.