1987 force 50 hp...little water from water pump

stevensmithnc

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Jun 8, 2009
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The water impeller is brand new but i still dont get a very good spray from the hole in the back. I also added a tell tale and the water doesnt spray it just kind of sputters out at idle and then sprays some when the throttle is opened up more. What should the operating temperature be maybe i will hook up a temp guage to test it too before i get it out on the water.
 

john from md

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Re: 1987 force 50 hp...little water from water pump

The holes on the back will just sputter as the exhaust is coming out of those holes also. They are relief holes for starting and idle. After the trottle is opened, the bulk of the exhaust comes out the snout.

Did you attach your tell tail to the plug on top of the thermostat housing? If so, the water should be coming out like a water pistol. If it is not, there may be an obstruction in the passage.

The operating temp should be @130 to 140 degrees.

John
 

stevensmithnc

Seaman
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Jun 8, 2009
Messages
73
Re: 1987 force 50 hp...little water from water pump

The water shoots out like a water pistol if you throttle it other than that when it idles it just kinda sputters water out. The water impeller is brand new. What if the seal on top of the water pump housing is bad would that cause this to happen it looked kinda rough when it was off.
 

john from md

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Re: 1987 force 50 hp...little water from water pump

If the seal was bad or if you had too much corrosion in the pump housing itself, water would bypass and you would not get the volume you require. However, if you are getting a good flow when the trottle is advanced, I would say go with it and just don't idle for long periods.

As long as you see something coming out of the tell tale you should be ok.

John
 

Mark42

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Oct 8, 2003
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Re: 1987 force 50 hp...little water from water pump

Regarding the pump housing and corrosion, in the OEM Force manual there are two diagrams of the water pump impeller, one at idle and another at speed. At idle, it shows the impeller is rubbing the sides of the pump housing as you would expect, and pumping water. But to my surprise, at speed, the impeller vanes fold over with the resistance of the water. They don't even come close to touching the sides of the pump housing. So most of the time, there is no seal against the pump housing, so even extensive corrosion should not have much if any affect on pump action at speed. Maybe at idle, but not at speed.

Anyone else ever see the diagrams I'm referring to?
 

john from md

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Re: 1987 force 50 hp...little water from water pump

Mark,

You are correct about the impeller bending with speed. Frank Acampora has stated this on a number of occasions and it is in my manual.

Corrosion causing pits on the walls only deteriorates the thick end of the impeller and usually is not an issue. However, corrosion on the top wall separators beween chambers will cause the pump to bypass to the intake side and that is the real problem.

John
 
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