View Full Version : Low Pressure Fuel Pump Quit

05-22-2016, 09:55 AM
Yesterday I went out to make sure everything was ready to go for the upcoming memorial weekend. I had repacked my drive shaft, so I got that tightened up and adjusted a couple bunks on my trailer since I had to get a new one due to rust. I had the boat out a couple weekends ago for about 20 min and that's when I realized I needed to repack the drive shaft.
Anyway, yesterday after being tied up to the dock while adjusting the packing and my trailer I had shut my boat on and off numerous times. Also I loaded it onto the trailer 3 times to check the bunks. Finally I was ready to go for a drive. Didn't even make it past the no wake zone and the motor died. It didn't sputter like I ran out of fuel but just died. Opened up the cover and noticed when I turned the key the low pressure pump wasn't whining like usual when it draws the fuel from the tank. I checked all the wires and everything was hooked up still but the low pressure pump would not run. A fisher man towed me the 40 yards back to the dock and I had to call it a day. This morning I was going to check everything and see if I need to order a new pump. But the first time I turn the key everything is working great!

Anyone have suggestions on what might have caused this?? I replaced the thermostat and high pressure pump this last winter. The temperature was at 160 when it died. What sensor could cause it to just die and not allow it to get power to restart?? Thanks for the help in advance

Engine Nut
05-22-2016, 12:26 PM
Can you hear either pump come on? They should come on together for a few seconds at key-up. If you can hear either pump come on it is possible the low pressure pump is coming on but you cant hear it because it is not pumping. There are vanes in that pump that are forced outward by centrifugal force when the pump spins. If the vanes are stuck in the hub the pump will not pump. You can take the top of the pump off and clean the pump vanes with carb cleaner to free them which should allow the pump to pump. Typically, if that pump spins and the vanes are free, it will pump fuel.

05-22-2016, 01:37 PM
No yesterday when it died I did could not hear the pumps trying to run. Also the boat did not sputter and die like it ran out of gas. It died like like someone pulled the kill switch. The engine would crank just fine but the pump wasn't working. Then this morning I turn the key and I could hear the pump turn on like nothing was wrong yesterday. So I don't believe it's the actual pump but maybe some relay or switch to it?

Engine Nut
05-23-2016, 11:08 AM
Not sure what year your engine is so I don't know where to tell you to look, but all of the engines have a fuel pump relay that is controlled by the engine ECM and turns the fuel pump on for a few seconds at key-up and again when the engine is cranking or running. If your engine is a 2006 or newer, there is a fuse box on top of the engine and the fuel pump relay is in that fuse box. If your engine is older, there are three relays attached to the ECM bracket. One of those three is the fuel pump relay. Look at the wire colors. The relay plug that has a pink wire in it is the fuel pump relay.

05-23-2016, 12:19 PM
Sorry should of mentioned the year of the boat. It is a 2001 Moomba Outback ls. I had seen the relays but wasn't sure which one was the fuel pump relay. I will check that relay and check the ground wires. Hard to trouble shoot when the next morning I went to work on it and everything worked fine.

05-23-2016, 01:34 PM
Not sure if the 2001 has a safety kill switch but that will kill the fuel pump but still allow the motor to crank.

05-29-2016, 08:02 PM
I replaced the kill switch and haven't had any problems this weekend. Thanks for all the input!