90 HP mariner losing prime?

[junkyardwarrior]

88 90 HP 3 cylinder 2 stroke Mariner. It's a 3 carb motor-single fuel pump and it's rigged on a 16' bass boat with a built in fuel tank.

FINALLY got it running properly. But when I pump up the fuel line to prime the carbs, it will start and run great. After running and then shutting the engine off, within a couple minutes the fuel siphons back out of the fuel system-it will restart but only for a few seconds, and then I have to pump the line up again. Temperature doesn't seem to make any difference, nor does how long the motor has run. It can be stone cold and I can pump the fuel line up, and within a few minutes I have to pump it back up again. Fuel pump is pumping fine (removed line from carb to verify).

I did have to replace all of the fuel lines. In the line from the pump to the carbs was one of those glass fuel filters. It had a tiny crack starting to get longer so I removed the fuel filter as the boat has a separator/filter installed next to the fuel tank. That is the only thing that I did-other than replace all the fuel, switch box, trigger, and repair the stator wires.

Any ideas?

 

[jerryjerry05]

Re: 90 HP mariner losing prime?

Replace the squeezie and then rebuild the fuel pump.J

 

[Silvertip]

Re: 90 HP mariner losing prime?

The primer bulb gets firm when you squeeze it because the carb float bowls fill with fuel and then the floats shut off the flow. The minute the engine starts, fuel begins to be "sucked" through the fuel line so the bulb immediately begins to go soft and it will stay that way unless squeezed again. When you restart the engine are you using the push to choke feature and raising the fast idle lever? Fuel will not siphon back out of the carbs to I suspect your starting procedure is at fault and not the primer bulb.