2004 200 OX66 prime problem

[Magnaflux]

Here is my problem. You can pump the bulb all you want and nothing happens. If you take the fuel line off the canister ( you can tell that the line has pressure in it) then pump the bulb until fuel comes out then hook it back up, the bulb will get tight and the engine will start. engine will run fine all day. Next day same problem the bulb will not be tight and you will have to start that process all over again. So here is what I have so far. I replaced all fuel line between the fuel tank and the bulb. Replace the bulb with a new Yamaha bulb. Still the same thing. Is there a check valve somewhere after the canister that could be stuck? Low pressure pumps bad?Any other ideas?
Thanks.

[99yam40]

do you point the arrow up on the bulb while priming?

[Magnaflux]

Yes. Any other ideas. It seems like the pressure in the line is keeping the fuel from getting to the engine.

[boscoe99]

If fuel is not moving through the primer ball and the ball is goodntite then the system is primed with fuel. No further fuel can flow. The float valve in the VST is closed and won't let more fuel in.

Does not matter if the ball is not hard however with the OX66 model. The VST will remain full of fuel. Fuel in the VST will start the motor and run it long enough for the lift pumps to pull fuel from the boat and in order to refill the VST.

I had a Mercury EFI model similar to the OX66. I did not use the primer ball but maybe once every three years when I changed the boat mounted fuel filter.

[Magnaflux]

Basicly the primer bulb will not pump fuel unless I unhook the fuel line from the VST. If I unhook the fuel line from the VST and pump the bulb until fuel comes out the fuel line then hook the fuel line back up then the VST will fill when I continue to pump the bulb then the bulb will get tight. Could the needle and seat be sticking? Other Ideas?

[boscoe99]

If the VST float valve is stuck closed then yes, you won't be able to pump fuel.

[Magnaflux]

I will check that. Thanks.