My Merc 250 just died idleing out to the no wake buoy It almost started back up but did not. I disconnected the bulb line to the fuel tank selector and pump the bulb and no gas came out. Shouldn't fuel come out if you pump the bulb?

Yes sir.

Are you sucking on an empty tank? I assume there are two in the boat since there's a fuel selector valve.

Be sure to check that the bulb is operating correctly. It should exhale air from the open end when you squeeze it, and the flapper on that end should seal when you release the pressure on the bulb; otherwise, it's not going to suck gas from the tank. Bulb failure is not an uncommon occurrence. I learned the hard way to spend the $$ and get a good one - like the Mercury branded bulb.

If a vent for a tank somehow becomes blocked, the fuel system will be unable to suck fuel from the tank. A simple way to check for this is to remove the gas cap of the tank you are trying to siphon gas from as you pump the bulb. If you can get fuel after a few pumps (to prime the hose) then you may have just identified a blocked fuel vent. Sometimes bugs or a small lizard can cause this, as examples.

Ok Guys I have changed out the fuel line with the bulb and when I prime the bulb it will not take air in order to pump bulb again. One squeeze and it stays flat. Could the end of the bulb line that is hooked up to the water seperator be full or something along them lines?

Does your boat have two tanks? Sound like your trying to pull fuel from a closed transfer valve?

The only way you can pull fuel from a closed transfer valve is if it is off or closed. It is neither

I have a left and a right and a off, I have tried both and both have plenty of fuel in them.

That’s why I’m ask Ranger. The cable going to the fuel transfer might have slipped and the valve is in the closed position. That’s where I would start. Mine quit working so I put a manual transfer switch in. I just have to reach into the battery compartment to switch tanks. Good luck!

Dumb question,but when you replaced the bulb did you get on in the right direction?

I did

CoolArrow,
It is acting exactly like you say. It is doing the same thing it did when the Tank selector went bad (two summer ago). I was just thinking no way another one has gone bad. So I started chasing other areas first. These Basscat's don't have the cable type they have a ball valve.
Really do appreciate it all of you trying to help. I am going to keep at it.

The line may be plugged in the tank at the filter

From the new bulb, trace the fuel line toward the motor to the first place there is a fitting. Disconnect that fuel line and put it down into a bottle such as a 2 liter soda bottle. Pump the bulb to see what happens. If you still do not get fuel, then the problem is behind the bulb, toward that part of the fuel system. If it works correctly, then the problem is in "front" of the bulb. Proceed based on test results.

Did you ever try priming the bulb with the fuel tank cap off for the selected tank? This would be to determine if the vent is blocked. If a vent is blocked, the bulb can't remove fuel from the tank due to suction-lock. This is a slim chance as you have two tanks, and both would have to be blocked.

Noticing that you have the same outboard model I do, I'll mention what I found. Just outside the cowling, there is an in-line splice in the fuel line. I'm told this is the standard interface point between the engine's factory installed fuel system, and the boat's fuel system. This may be hidden by a sheath over the cable & hose bundle going into the engine cowling. This is an excellent point to disconnect (and put the end in the bottle) to try pumping the bulb. This way, you can check the system all the way up to the engine.

How hard is it to get to the ball valve, and to take a fuel line off of it to look at the ball movement to check it? It seems your failure is not related to one tank alone, so I'm focusing on points that would fit that description.

If you just changed the bulb, did you install it backwards. Prime bulbs are a one way deal Should be an arrow on it.