2004 DF140 fuel pump problems

[merlebh]

I recently purchased a boat powered by 2004 Suzuki DF140. After a few weeks the engine started surging at higher rpms. After researching I decided to target the VST. So, I pulled the intake manifold and removed the VST. Fuel in it was clean. I checked and cleaned the needle valve, checked the float height and applied 12v to the high pressure pump and it operated. I also changed the lp fuel pump, lp fuel filter, high pressure fuel filter, water separator fuel filter, injectors, and spark plugs. After getting it all put back together I decided to hook up the muffs and start it to check for leaks, but it wouldn’t start. It sputtereda couple times when I squeezed the primer bulb but that’s it. Seemed like it wasn’t getting fuel so I checked voltage at the plug to the hp fuel pump and I get nothing with the key on. But, when cranking the motor I get 10.1 volts. I also connected 12v directly to the hp fuel pump nothing happens. I know I need a pump. But, what could be causing the low and no voltage issues at the connector. Thanks in advance for any help you can offer.

 

[William01]

Low voltage could be due to the draw from the starter and possibly a less than perfect battery? As far as no voltage not sure, I think the hp fuel pump is controlled buy the ECM based on a bunch of inputs from various sensors.

From a 2009 DF90A Service Manual. Not your engine but should be close enough to give you an idea.

 

[merlebh]

Is voltage to the pump when key is turned to the “on” position constant or momentary?