Air in fuel lines

[RayFinkle]

Hi All,

First time poster on this forum...
I have a 95 seadoo SPX that when I got it had been sitting for years. I immediately changed out all the grey fuel lines, rebuilt the carb with genuine Mikuni parts and got it running. On the trailer it runs fine...in the water different story, the throttle is super unresponsive and then will surge to a million rpms. Diving in deeper into this issue I realized that there is air in the fuel lines and barely any fuel in the return line. I have eliminated the water separator and fuel selector switch as culprits...what am I missing here? It seems as if the carb is starved perhaps? Should the return line be full of fuel?

Appreciate any expertise on this matter

Laces out-Ray

 

[Grim]

Did you check the fuel filter? There is also a filter at the end of the baffle, look at your tank and make sure there isn't a lot of debris at the bottom.

 

[POPPS]

remove the in fuel line and alternately, the reserve,,,insert a 1/4 fuel line that will come out of the hull,,,then gently blow into the baffle…don’t remove both at the same time..you will be able to clear out any debris that way..if you too hard,,,you can blow the bottom filter right off..did you run a hose directly from the in fuel pickup to the carb?

 

[RayFinkle]

Did you check the fuel filter? There is also a filter at the end of the baffle, look at your tank and make sure there isn't a lot of debris at the bottom.

Thanks for the reply. I have eliminated the fuel filter/water separator. I can’t see inside the tank for debris as the tank is varnished color now. Would it be worth pulling it and cleaning?

 

[RayFinkle]

remove the in fuel line and alternately, the reserve,,,insert a 1/4 fuel line that will come out of the hull,,,then gently blow into the baffle…don’t remove both at the same time..you will be able to clear out any debris that way..if you too hard,,,you can blow the bottom filter right off..did you run a hose directly from the in fuel pickup to the carb?

Thanks for the reply!
I did try blowing into the tank, also currently I have a direct line from the pickup to the carb.

 

[RayFinkle]

So I think I realized what my problem might be...when I rebuilt the carb I used the below kit...This doesn't seem like a genuine mikuni kit which might be leading to my problems...anyone use the below kits? I ordered a genuine one.
SeaDoo Dual Mikuni Carburetor Rebuild Kit Needle Seat Base Gasket 1995-1996 SPX

 

[mikidymac]

I don't see anything that would indicate it is genuine Mikuni.

 

[JC-SUPERJET]

Genuine Mikuni SBN Kits have the Regulator Diaphragm Center Buttons anodized. The Knock-Off Diaphragms don't.

Genuine Kits don't come with Needle Valves. Sold Separately.

And the Genuine Kits come with Mikuni Stickers ; )

 

[RayFinkle]

Ah! I think this explains it all now.
I ordered a genuine one! I’ll report what happens!

 

[mikidymac]

Genuine Mikuni SBN Kits have the Regulator Diaphragm Center Buttons anodized. The Knock-Off Diaphragms don't.

Genuine Kits don't come with Needle Valves. Sold Separately.

And the Genuine Kits come with Mikuni Stickers ; )

View attachment 59208

I have been seeing some of the knock off ones have the red button but it isn't the exact same color. The fakes are getting clever.