I have a dumb ? 1983 evenrude70hp water pump

[boatin]

replaced water pump. everything looks fine and I was carefull not to get sealant in the wrong places......but Im turming the shaft clockwise by hand to check it out and by golly it takes both hands to even turn it!!!Took the pump back off and the shaft turns easely. Put pump back on and same thing . Surely the pump doesnt load the motor that much.....does it?

 

[DJ]

Re: I have a dumb ? 1983 evenrude70hp water pump

boatin,<br /><br />That is a positive displacement pump. It does put a load on the engine. However, it is much easier to turn when there is water going through it.<br /><br />That is why you never want to turn over your engine with the pump dry.

 

[ob]

Re: I have a dumb ? 1983 evenrude70hp water pump

Yup.They're pretty tight because of the design of the offset flex impeller.But,you should know that,you loaded new impeller into the cup ,right?

 

[boatin]

Re: I have a dumb ? 1983 evenrude70hp water pump

Thanks guys,<br />I guess its normal to have that much of a load with no water going through. It just seems like some brilliant engineer could come up with a better idea....................................

 

[ob]

Re: I have a dumb ? 1983 evenrude70hp water pump

One would think.But ,If you consider the suspended silt and sand these outboards are subjected to ,the current design has a proven track record.Centrifugals are not feasible because they can't deliver instant volume on a system that empties out between uses,and many other positive displacement designs would fall prey to the abraisive side effects of suspended particulates.Crude design for a crude application.<br /><br />By the way,I didn't think it was a dumb question at all.It shows observance on your part.

 

[boatin]

Re: I have a dumb ? 1983 evenrude70hp water pump

Thanks OB. That was a very good and informative answer!! My old teachers in school said that there are no dumb questions, but I question that while raising three children.......or maybe they are trying to appear dumb to get me to do their homework for them.

 

[rodbolt]

Re: I have a dumb ? 1983 evenrude70hp water pump

Hello<br /> yep now imagine that impeller running in the cup at 1000 rpm dry. takes less than 30 seconds to melt the housing and you only have to do it once. that pump is actually a positive displacement at low speeds and a centrifical at high speeds. that is why the poor little rubbers are so critical. the vanes must remain flexable or you no longer have a pump.did you spay some dish soap in the cup before loading the impeller? I have found that it helps a lot while assmbling.<br /> good luck and keep posting

 

[seahorse5]

Re: I have a dumb ? 1983 evenrude70hp water pump

Did you lube the stainless steel cup in the water pump housing so the impeller turns easier? The Johnson/Evinrude Triple Guard grease does not affect the rubber in the impeller like other substances might.

 

[boatin]

Re: I have a dumb ? 1983 evenrude70hp water pump

I did put a dab of grease in housing....just wasnt sure if the pump should that hard to turn....like I said , I had to use both hands. I reinstalled it so it must be normal. Thanks again for all the input!!!