1998 seadoo xp 951: Carburetor fuel pump barely works

[JC-SUPERJET]

The Check Valve Discs are cut from Plastic Sheets that come in ROLLS.

What that means is that the Check Discs will not be perfectly flat due to curl deformation.

This implies that there is only one side of the Disc that will lay flat and seal tight, and that is the side with the Sharpie Mark on them.

Another way to determine correct Disc Side to face down, is to mate the concave side to the Flange.

This will ensure a good seal because, the built-in "camber" will seal tight since the Disc will be under tension against the Flange when forced to lay flat by the Rubber Pin.

 

[mikidymac]

Yeah I’ve got the diagram, and I’m positive it’s assembled correctly. I could see just by looking at it, that my disk wasn’t sealing because it was warped and because the plug wasn’t holding it down enough. Not sure about the corrosion, I’ve tried to clean it so as far as that goes I think I’ll take my chances. If it doesn’t work, then I’ll look into doing something like you did to get the corrosion off.

So just to be clear, you are not rebuilding the carbs with all new parts?

 

[dash75966]

No I have already done the full rebuild with all new parts from osd marine. I just messed up the fuel pump, by warping the disk which made it not seal. Which side is up on the disks again? In the rebuild guide on here is says marked side up, but JC above said marked side down.

 

[etemplet]

I can hardly differentiate which side is which on the discs and as to which side is marked even that is difficult. i'm not so sure that whoever or whatever is marking these things is all that reliable. LOL I trust my eye.

On the installation of the grommets that is a very tedious job for me and I've tried different methods. I have the tool but that alone doesn't get it done for me because you can't push hard enough to get the grommet into position or you poke a hole in the grommet. I end up using the tool and while holding pressure push the edges with a small screwdriver. I've damaged a few. Total PIA for me. One slip and the disk is done.

 

[mikidymac]

The marked side goes up so not touching the aluminum.
To test the mark put some brake cleaner on a rag and see which side removes the ink, that is the "up" side.
All in the carb rebuild thread.

 

[dash75966]

I’ve changed the faulty disk, and I’m sure the check valves are functioning correctly. I only have one one direction of flow when I blow inside the fuel hose nipple, so it’s working. However when I make the pulse with my mouth to test the pump, I feel no suction at the fuel intake. Is there something I’m not doing? I want to just put it on and see if it pulls from the engine but because that’s so difficult with the exhaust in the way I want it to be 100% when it goes on. Someone please help me I’m just suffering at this point.

 

[TheGTIjetguy]

To be honest, you won’t be able to feel any suction. Especially when the engine isn’t running. The pump operates on a pressure differential principle. A slight, very slight vacuum in the pump draws the fuel up from the tank.
When it is back together, 30 seconds to a minute of cranking. (In bursts for the starters sake) will pull fuel into the carbs.
You can fill the water fuel separator/filter with fuel to speed up the process before installing the filter cup if you’d like.

 

[dash75966]

I’ve pumped fuel into the filter already, so it should work. But you’re telling me I should just go ahead and put it on? One thing I’ve already done was put the carb on top of the engine and hooked the lines up to see if it would pull and it didn’t. The carb wasn’t level however, so maybe the needles not sitting messed up the vacuum or something? I just hate taking the thing off but I guess if it’s what must be done then I will do it. Just wanted to confirm before I go and put some time into it tmrw.

 

[TheGTIjetguy]

Hmmm, level shouldn’t have anything to do with it. Diaphragm carb are designed to operate at any inclination. (Think chainsaw).
I think you may be looking at a small leak in your fuel system somewhere that breaks the vacuum and negates the pump.
Have you replaced your fuel shutoff valve? That is a common failure point for air leaks. Also, how full is your tank? The pickup line inside the tank could be broken above the static tank fuel level, therefore not allowing any fuel to flow.

 

[dash75966]

Tank is about a quarter full, I know it picks up fuel and theirs no leak, because I put a clear line on the end of the filter and used my mouth to suck the fuel up, then I just plugged it and let it sit to see if there was any air leaks and it was good. I then proceeded to test the pump using a cup of water and food coloring, and I pulled water straight up the line. So I feel like it has to be an air leak somewhere but I have no idea I where it could be. It just held the water in the clear line with no leaks so it can’t be a pump failure. But since I’ve checked all the air leaks and pump functionality, I might consider just putting the carb on and trying it.