1987 V4 Crossflow Water Pump Assembly

[Solittle]

I just got finished testing one of my engines after replacing the T-stats and water pump. This engine had been getting hot due to a stuck T-stat on the port bank. The engine runs fine (on the muffs) and the temp (as measured by a laser temp gage) is around 139-143 but the water pressure is very low at the pressure gage and pisser. The water pump is a Sierra and did not come with a parts diagram. I may have put the o ring that should go beneath the splines on the top of the drive shaft between the impeller and the stainless plate. If so in addition to being stupid would this be the cause of the low pressure?

I think I know the answer but not going to tell - - for now anyway.

 

[funpilot]

Re: 1987 V4 Crossflow Water Pump Assembly

In my opinion, yes. The impeller should run against the stainless plate, or water will escape there instead of running in the impeller pump section.

So, what is your answer?

fp

 

[JUSTINTIME]

Re: 1987 V4 Crossflow Water Pump Assembly

yep sounds like u rolled the water pump housing o-ring a little bit

 

[OBJ]

Re: 1987 V4 Crossflow Water Pump Assembly

In the original pump assemblies, there is an oring that goes between the impeller cup and housing....that is....you must remove the impeller cup to replace the oring.

In NEW complete pump kits, there is an oring that also goes between the impeller and impeller plate, however, the impeller is made to accept the oring on the bottom.

 

[Solittle]

Re: 1987 V4 Crossflow Water Pump Assembly

Hmmmmm - - Seems we got answers both ways. My inclination was the o ring should not be between the impeller and the plate as funpilot and justintime point out. Now along come OBJ's information.

Hmmmmm I do remember a recess at the bottom of the impeller and that is where I think I put the o ring. But I also remember thinking as I tightened the cover bolts that the space between the impeller and plate looked odd.

For what it is worth I replaced the complete pump. I do not know who made the old pump but the outer housing is sort of white in color. The new pump is a Sierra and the housing is black.

For OBJ - Both the old and new pumps have the o ring between the cup and housing. This o ring is between the impeller and plate. What would the function of this o ring be and what would be the impact if I remove it? I plan on inspecting it in any case as my memory is not that precise. I really don't care much one way or the other but I do want to make sure I have good pressure.

 

[ezeke]

Re: 1987 V4 Crossflow Water Pump Assembly

I agree with OBJ.

On the newer BRP impeller, part 5001593, there is a deep recess for the 'O' ring on one side only. The other side has a shallow recess.

If you look at the waterpump diagram for the 1987 150 crossflow, you can see that there was no 'O'ring below the impeller. That impeller is now superseded by the aforementioned 5001593.

If you do not have an impeller with a deep recess on one side, my recommendation would be to not use the 'O'ring below the impeller.

The complete pump and diagram that I am looking at is the BRP 5001595. It does have the 'O' ring in the diagram below the impeller, and it also has the wider and thinner 'O' ring above the cup.

 

[OBJ]

Re: 1987 V4 Crossflow Water Pump Assembly

If you have a gap between the impeller plate and impeller with the oring underneath, then you have got the generic form of the original impeller. Remove the oring underneath as ezeke posted. The impeller should set flat against the plate.

The new set up with the oring beneath the impeller, I believe, acts as a seal around the area of the impeller plate that the drive shaft goes through. This should increase pressure (some) and also keep escaping pressure off the top seal around the drive shaft.

(sounds logical anyways)

 

[Solittle]

Re: 1987 V4 Crossflow Water Pump Assembly

You guys are great!!!