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Discussion Starter · #1 ·
I've got my new rebuild kit and there's no instructions on how these gaskets go in. I had it apart last year, but I don't know if it was correct then?
One reason I ask, it every picture of these gaskets show the gaskets materials in order ie: gasket, plastic membrane, rubber flapper valve.
My reasoning makes sense that it should go together in that order to provide a seal to each side of the metal plates.

But the one I worked on had only the rubber (and maybe gasket) then plastic. :dunno:

Anyone have a diagram on how these are supposed to go together?
s/t
 

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I know you are working on a Scorpion, but try looking at the Polaris parts diagram. I went to 1985 for the Indy 400 and found an exploded diagram of a Mikuni round pump, that may be just what you are looking for.

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Mikuni "sandwich"

Sport Truck,

My Mikuni (early Polaris) fuel pump was assembled as follows:

Top cover
gasket
diaphragm
pump body
diaphragm
gasket
bottom cover

When you do yours, be sure you remove any and all "cheese" from corrosion, especially if your pump has zinc castings.

Mine had alignment tabs in both the castings and the top cover gasket. Make sure they all line up. (see the fifth pic.)

In the pump body, if your round flapper valves and the rubber "darts" that attach them are missing, the flappers are installed AWAY from the counterbored hole- this is where the point of the "dart" goes.

I install them by lubricating the "dart" with a little WD-40 and putting the plastic straw from the WD-40 into the hole in the "dart". Then the flapper is laid over the hole and using the straw, the "dart" is pressed into place.

Hope this is some help to you.

-Strato-
 

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Discussion Starter · #6 ·
Sport Truck,

My Mikuni (early Polaris) fuel pump was assembled as follows:

Top cover
gasket
diaphragm
pump body
diaphragm
gasket
bottom cover

When you do yours, be sure you remove any and all "cheese" from corrosion, especially if your pump has zinc castings.

Mine had alignment tabs in both the castings and the top cover gasket. Make sure they all line up. (see the fifth pic.)

In the pump body, if your round flapper valves and the rubber "darts" that attach them are missing, the flappers are installed AWAY from the counterbored hole- this is where the point of the "dart" goes.

I install them by lubricating the "dart" with a little WD-40 and putting the plastic straw from the WD-40 into the hole in the "dart". Then the flapper is laid over the hole and using the straw, the "dart" is pressed into place.

Hope this is some help to you.

-Strato-
That helps some.... Mine is the rectangle model:eek:
But I'm sure mine was put together wrong last time (and the time before it got it) but it ran ok.
The gasket(s) should go against the metal body with the clear piece sandwiched between them. The alignment is pretty much fool proof, as the cover has tits that allow it to on one way.
S/T
 

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That helps some.... Mine is the rectangle model:eek:
But I'm sure mine was put together wrong last time (and the time before it got it) but it ran ok.
The gasket(s) should go against the metal body with the clear piece sandwiched between them. The alignment is pretty much fool proof, as the cover has tits that allow it to on one way.
S/T
My bad! Should have asked you what pump you were running. :eek:

The Mikuni pump for my SS 440 is single rectangular, and I just renewed it. If you want some confirmation on how yours goes together, I can pull it down and snap some more pics. They're really easy to assemble/disassemble until they've been clamped together and had fuel run through them for a while. Rectangular pumps generally don't use the dart/flapper assembly. The flappers are normally cut right into one or two of the diaphragms.

Let me know what you think.

-Strato-
 
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