1974 mercury 40 hp pumps eratically with a new pump kit

[freddy1950]

I just installed a complete new water pump kit in my 74 Merc, hooked a hose up to the lower unit, turned on the water and started the engine it pumps out in a steady stream but it pumps out erratically , do I have an impeller blade or two going in the wrong direction? Thanks, Fred

 

[Texasmark]

Re: 1974 mercury 40 hp pumps eratically with a new pump kit

Might or you may have a piece of the old impeller in there, or some other blockage of the water passages; crud you sucked up or congestion due to corrosion.

We discussed this the other day and I think that if you had a blade backwards, the first time you went to WOT in the water, the force of the driveshaft and inlet ram water will put them all in the right direction.

Mark