kicker motor runs out of fuel...

[longshanks]

It looks like I need some help in troubleshooting my fuel supply!

My main motor (90HP classic carb'd Mercury) and my kicker motor (9.9 mercury 4-stroke) are fed by a single fuel tank and fuel line that is routed through a fuel/water separating filter and then 'Y'd off into 2 lines that distribute fuel to either one motor or the other. Fuel distribution to the kicker or the main motor is switched by inline ball valves.

Lately, when I am using the kicker motor, I prime it using the inline bulb and it runs for a few minutes before running itself out of fuel. If I pump the bulb when this happens it will come back to life and run for a while longer before the same thing happens again. No problems with the main motor, and when I run the kicker off a stand-alone tank and hose it runs fine. This tells me that there is a problem with my fuel supply. I suspect that there is air entering the short portion of fuel line between the filter and the kicker motor, but I am open to suggestions about what may be causing this.

I replaced the inline fuel filter recently but there is no improvement. Could there be some sort of issue with a fuel pump?

 

[oldman570]

Re: kicker motor runs out of fuel...

Trouble with the fuel pump should have showed up when the motor was run on a seprate tank. Your sucking air somewhere between the Y and the fule hookup on the motor. Try replacing the conector on the fuel line to the motor as I've had trouble with some of them.
Oldman570

 

[d.boat]

Re: kicker motor runs out of fuel...

Trouble with the fuel pump should have showed up when the motor was run on a seprate tank. Your sucking air somewhere between the Y and the fule hookup on the motor. Try replacing the conector on the fuel line to the motor as I've had trouble with some of them.
Oldman570

Dredging up a somewhat old thread to give a big +1 to oldman570. Fuel connectors are not all created equal, and I've found that common aftermarket connectors labeled for Merc, don't work!

I have the exact same setup (main tank, water filter w/ two outputs, main engine and kicker) and the exact same problem. I had installed an aftermarket fuel connector to my main fuel system for my new 9.9 Merc kicker last season (replacing the old bayonet style from my old Merc). It worked fine all summer, but I only used it 4 or 5 days. I did notice that it seemed a little finnicky starting toward the end of the season, but it still started so much easier than my old kickers, that I just didn't pay attention.

When I went to use it this summer, it wouldn't prime up and start at all. I heard air leaking when I pumped the fuel line bulb, and then noticed that the O ring on the fuel part of the connector was chewed up. Instead of thinking about it, and because it was more convenient, I went to the local sports store and bought another aftermarket connector. It worked perfectly.

But then, after about 5-10 "connect/disconnect" cycles on the new connector, out on the water, the kicker wouldnt' start or run on the main fuel system even though the main engine ran fine. Still stupid, didn't even think of the connector, but just trolled w/ the main for the rest of the day.

Got home, started it up on the OEM auxillary tank to begin trouble shooting the problem - started and ran perfectly! Switched to boat system, started fine, but only ran for a few minutes, until the carb ran out of fuel. Brilliant flash of insight: examined at the aftermarket fuel connector: same chewed up O ring! Compared aftermarket connector (labeled "mercury") and it was distinctly different than OEM.

aftermarket:

There is a little ball valve surrounded by an O ring - the O ring gets chewed up after several connect/disconnects. It causes air leak, lack of suction and fuel starvation.

OEM (and some aftermarkets do look like this):

Note the distinctly different fuel portion of the connector. It doesn't have the same ballvalve/O ring connection. I also found that it clips onto the engine much easier than the aftermarket connector - probably relates to the O ring issue - ill fitting ->chewed up O ring?

So, make sure you get the right aftermarket connector that looks the same as the one on your OEM auxillary tank, or buy an OEM connector from your Merc dealer (costs ~$10 instead of ~$5, well worth it!)