1991 Seadoo Sp No Fuel To Carb Chamber

[whoismichael]

I have a 1991 Seadoo SP I just rebuilt the carburetors and I’m not getting any fuel to the inside of the carb! Like the inside inside. I get flow through the inlet and outlet and my pulse has to work or the inlet and outlet wouldn’t be flowing. I did a pop off pressure test too. What could be the problem? How does the pressure work to open the pop off. I don’t get how it gets pressurized in the carb in order to open the needle.

 

[mikidymac]

Did you use a genuine Mikuni rebuild kit?

 

[whoismichael]

Did you use a genuine Mikuni rebuild kit?

Yes I did it gets flow through the carb inlet and outlet and pulse obviously is working hence the flow. It just doesn’t wanna work in the chamber. Is the fuel supposed to trickle out of the carb or spray?

 

[mikidymac]

Neither.
The vacuum of the engine pulls the fuel out.
If you aren’t getting fuel out of the carbs, either your needles and seats are stuck, wrong springs or something is clogged.

 

[whoismichael]

Neither.
The vacuum of the engine pulls the fuel out.
If you aren’t getting fuel out of the carbs, either your needles and seats are stuck, wrong springs or something is clogged.

Okay so how does it go out of the carb? In what way? When I throw the tester on I get like a spray coming out. Also is this a problem with the pump at all or just the chamber side. I don’t really want to take the pump side off and mess up the gaskets if nothing is wrong with it.

 

[POPPS]

You cannot really mess up the pump side gaskets,,listen to miki,,,pull the carbs and start from square one,

 

[rbowes1]

When you say you are not getting any fuel to the 'inside inside' of the carb do you mean the little circle venture in the center? That is the high-speed jet and you shouldn't see fuel there if it is just cranking trying to start. The fuel for starting and idle goes through the bypass port and the low speed jet below on the side. As mikidymac says it is the vacuum from the engine that creates low pressure in the carb which causes the air pressure outside the carb to push on the diaphragm and open the needle valve. If you put enough pressure using a pump or primer bulb on the fuel inlet it will open the needle valve and spray fuel, like with the pop off test, but that is just a test to make sure the needle valve is working and the spring pressure is correct, that isn't really how it operates when running. Here is a description of how the carbs work https://www.mikuni.com/pdf/sbn_manual.pdf

Are you sure you aren't getting any fuel? You can take the spark plugs out and crank the motor, you should smell gas and see some if you put a rag over the plug hole while cranking.