Primer bulb not getting hard or goes soft while running

[jerseydevil]

Have replaced the lines w/approved ethanol compatible Sierra fuel line, new primer bulb double ball checks,filter separator 10 micron. When bulb does get hard out board runs but then the bulb goes soft & o/b stalls.I've spoke to some who say that the bulb has to be vertical vs horizontal.at all times? Some say check tank & o/b connections pick up tube is fine. lastly the fuel pump needs to be rebuilt? Want to make sure the basics are covered before tearing into o/b fuel pump or internal fuel lines. Any suggestions are appreciated.

 

[steelespike]

Is the filter separator between the primer and the motor? It is normal for the primer to get soft in operation but if it collapses there is a blockage
on the tank side of the primer. Could be sucking air, not unusual for a quick connect to leak air and not leak gas.Take the separator out see if it runs.

 

[jerseydevil]

The filter/separator is before the primer. Then the outlet of the primer goes to the motor connector. Does the bulb orientation matter if it's vertical or horizontal?

 

[Frank Acampora]

Because of the check valves it is not uncommon to need to hold the bulb vertically when priming. Once the engine is primed and the bulb filled with fuel it will work in any position. Are you using one of those new "ventless" tanks? If so, check that air can get into the tank while running. If not a ventless tank check to be certain that the vent is open.

 

[jerseydevil]

Yes the vent is open. Bulb loses prime while running as well?

 

[ondarvr]

The bulb will become soft when the motor is running, that is normal. Have you tried squeezing the bulb to keep it running, if this works you either have a bad fuel pump or an air leak.

 

[Frank Acampora]

Just to clarify: is the bulb simply getting a bit soft or is it collapsing? Under normal running conditions, the bulb will not stay rock hard. It should stay "inflated" though. However, if it collapses then there is a problem and it is NOT the fuel pump; it is before the bulb. Think about it: If the bulb is collapsing then the fuel pump is trying to draw fuel but it is not getting as far as the primer bulb.

 

[jerseydevil]

Hey Frank/ondavr the bulb gets hard motor starts & while I'm running the motor starts to quit till I squeeze the bulb a few times it starts running again? The bulb goes soft but doesn't collapse.

 

[ondarvr]

That tells you where to look.

 

[steelespike]

I would suspect the pump or the quick connect and lines to the pump.