Suzuki 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. No fuel in the VST when opening the drain valve. 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.

 

[Fj40fiji]

My Mercruiser has a sensor that gives it signal when the engine is cranking or running, and won’t power the fuel pump without that signal. Likely you shouldn’t get power with the key in the on position and not running. I’m not sure on the low voltage, but would keep in mind that the starter is consuming most of the available current when you are cranking it. Maybe 10.1v is enough to get fuel started. I’m curious what voltage you read across the battery terminals is when you are cranking.