Fuel Pressure - Main Motor & Kicker

[vman11]

So when winterizing my boat I noticed one of my fuel line bulbs (kicker) would pressurize but the other (main power head) would not. So I could run the main motor, I simply switched the fuel lines as I had assumed the bulb failed on the main line.

However, the bulb that worked previously (kicker) would not pressurize on my main motor and the mail motor bulb that did not pressurize before now did on my kicker.

I haven't done further research on what could be happening but thought I'd see how others have tackled/troubleshoot this in the past.

[Surface Tension]

Is the main outboard trimmed out(up). If so trim in and then try it.

Otherwise.

Inlet valve (needle and seat) isn't closing. Stuck valve or float. Debris in the valve or warn.

[Pat K]

On my gas line the bulb doesn't pressurize if it is lying in it's normal horizontal position in the slashwell when you squeeze it. If you hold it vertical and squeeze it it does pressurize.

[vman11]

Both motors are trimmed down.

[PropsterII]

Not sure what your engine is, but identical situation on my '95 Merc 150 and 9.9 kicker this fall. Tried the things I could do - fuel filter (water separator), check fuel line (I replaced with the good stuff a few years ago), new bulb. Had to bring it in and wound up being the needle in the secondary fuel pump like Frank said. I couldn't have diagnosed that, nor fixed it.