[MikeMo]

I have a 1996 9.9 4 stroke evinrude (trolling motor)on the back of my 17' Wilker (powered by a 2002 135 Mercruser).Last summer a dealer replaced the diaphram in the 9.9, as it wouldn't run. This spring the motor ran for 3 hours, then quit. I have added a water separator and have approximately 4 feet of gasline to the 9.9. The primer bulb goes flat after running for a short while. The motor dies a slow speeds. Any suggestions as to how I keep this thing running!ThanksMikeM

[rickdb1boat]

Check the vent on the fuel tank and/or replace the primer bulb. Are you running the portable off a separate tank?

[MikeMo]

I am running the 9.9 off my main tank. The main fuel line goes to a water separator where it is split, one line feeding the mercrusier, while the other feeds the 9.9. There is one anti-siphoning valve where the fuel line leaves the main tank.I shortened the line to the 9.9 - by 5 feet - which seemed to make some difference, but it still stalls out after running a couple of minutes. The primer bulb goes flat.

[OBJ]

SilverM....if the main engine runs OK, the pump on the 9.9 may not have the pulling power to get the fuel through the filter. Try a protable can and see if it makes a difference. Ya' might check the primer bulb is in good shape to....no lose valves.

[Bass Runner]

If you are trying to run your outboard on a closed sys. it won't work, your inboard has a fuel return to the tank, unvented, your outboard needs a vented sys. I would just throw in a 6 gal tank for the out board and plug the line you have running from your main tank.

[DHPMARINE]

I think the problem will go away if you install a fuel shut off valve in the line going to your Mercruiser.The 9.9 is running off the line to the Mercuiser then sucking air from its carb.Any fuel pump will suck air before liquid..DHP

[DJ]

Ditto, what DHPMARINE said.

[MikeMo]

Thanks for the help people!!Would the following work?Place an anti-siphoning valve between the water separator and the main engine as opposed to putting a fuel shut-off in that line.Should I take the anti-siphoning valve out of the main fuel line going from the fuel tank to the water separator?Thanks again!!MikeM