1971 evinrude 6hp water pump

[sandquino]

i have just replaced the impeller in the pump but the water pressure produced is not high enough to get water up into the powerhead.Does anyone have any ideas why this may be?

 

[Xcusme]

Re: 1971 evinrude 6hp water pump

Welcome to iboats!

Be sure the water level in your test barrel is high enough. Water must be ABOVE the water pump for proper operation. Be sure the water tube going into the water pump is inserted. Check to see if the impeller drive key is installed.

 

[sandquino]

Re: 1971 evinrude 6hp water pump

thanks for that but i'v checked that sort of stuff several times and is ok this is a really weird problem i just cant figure out

 

[Xcusme]

Re: 1971 evinrude 6hp water pump

OK then....try adapting a rubber hose onto the end of a garden hose. Fit other end of hose on water tube and turn on the water. This will push water up tube, past water tube grommet and through power head to confirm no blockages.

Remove lower unit and place in water bucket with enough water to fully immerse water pump. Spin drive shaft clockwise with drill and short piece of rubber hose on drive shaft splines, does water pump?

 

[Vic.S]

Re: 1971 evinrude 6hp water pump

At the risk of repeating what has been said or what you have checked.

Pump body undamaged and making a good seal around its periphery?
Water tube to pump grommet in good condition and making a good seal?
(Impeller is driven by a pin rather than a key I think so should be no problem there)

My problem with a 6hp, but a later model, is the grommet at the top of the water tube. Corrosion around it squeezes it over the top of the tube until it completely shuts off the flow. Testing with a garden hose on the water tube will confirm. Take the thermostat out while you do that and leave the cover off to make sure you get a good flow up to there.

The small water channels in the head can become choked with scale and corrosion. Has not yet happened to me but I have been shown pictures of one where that has happened.

 

[F_R]

Re: 1971 evinrude 6hp water pump

Pump housing worn? Stainless plate bent? Bleed hole in pump housing between outlet and center cavity blocked? Sierra Impeller? Sierra made a bunch of impellers that are too thick and they don't seem to think they should recall them.

 

[sandquino]

Re: 1971 evinrude 6hp water pump

I tried the lower unit in a bucket of water test , and water barely trickled out the top. I think i'll strip it down and check all the sealing again