No Start Condition

[Thomv]

Went out Sunday for Father's Day in Tampa Bay. Boat behaved nicely throughout the day. We decided to take a ride over to the other side of the bay to have some food. We shut off the boat and when we got back from eating both motors turned over and fired up for about 2 to 3 seconds and then stalled. It appeared that we were out of gas even though we got gas before going out. The fuel guage read half a tank of gas. We decided to go across the street and put in an additional 10 gallons just in case the fuel guage was incorrect. Still no luck. There was another boater next to us who offered to tow us to a close by ramp. Both motors are the 8.1 MPI fuel injected units built in 1999. Any help with this would be most appreciated. I know both motors have their own electric fuel pumps but how could both fail at the same exact time

 

[alldodge]

Went out Sunday for Father's Day in Tampa Bay. Boat behaved nicely throughout the day. We decided to take a ride over to the other side of the bay to have some food. We shut off the boat and when we got back from eating both motors turned over and fired up for about 2 to 3 seconds and then stalled. It appeared that we were out of gas even though we got gas before going out. The fuel guage read half a tank of gas. We decided to go across the street and put in an additional 10 gallons just in case the fuel guage was incorrect. Still no luck. There was another boater next to us who offered to tow us to a close by ramp. Both motors are the 8.1 MPI fuel injected units built in 1999. Any help with this would be most appreciated. I know both motors have their own electric fuel pumps but how could both fail at the same exact time

First thought is there is an electrical issue. Do you hear the fuel pump turn on and any beeps?

 

[Thomv]

That is the first thing I am going to check tonight. After looking at the manual this morning, before heading off to work, it did mention the pumps will turn on for a few seconds when you turn on the switch to the on position. If I don't hear them turn on what should I look for first?

 

[Watermann]

A bad fuel pump relay is what I would check for.

 

[dubs283]

are there separate fuel tanks, or just one for both??

 

[Thomv]

I believe there is only one fuel tank.

 

[DaveG55]

Well, I'd think that an electric fuel pump would be fuse protected so that's what I'd check first, then relays, then id get a DVM and start checking voltages and continuity.

 

[Thomv]

Well, I'd think that an electric fuel pump would be fuse protected so that's what I'd check first, then relays, then id get a DVM and start checking voltages and continuity.

I think it is still a situation as simply running out of gas even though the fuel guage was reading half a tank. By the time I got it home both engines started up without any hesitation and ran fine while flushing them out. I think what happened, and I may be wrong, is that both screw on fuel filter canisters completely drained and while trying to start both motors I did not crank them long enough for the canisters to fill up with fuel thereby starving the fuel injectors of fuel. When I did try and start both motors they would fire up for only 1 second and then stall. I am hoping this was what was happening. I am also going to try and open up the fuel tank and see if I can see how much gas is actually in the tank besides the 8 to 10 gallons of fuel we ended up putting into the tank at the dock. Is it possible to have a fuel sending unit off by that much? Is there a way to troubleshoot to see if it is giving me the correct reading? I have another post concerning a leaking water pump that also gave me trouble while out on the water.

 

[DaveG55]

If electric fuel pumps on boats are anything like cars you should be able to simply turn the key on for a few seconds before actually cranking the engine over to fully pressurize the system.. Once the engine is cranked any trapped air would be displaced within a revolution or two. Are both pumps powered by the same relay?
Or perhaps they share a fuel pick up that became clogged and the tow and drive home dislodged the blockage?

 

[Bt Doctur]

tank has to be 300-400 gallons, right?

 

[Thomv]

tank has to be 300-400 gallons, right?

No, 150 gallons. We usually only put in about 50 gallons at a time which is around $175. Definitely not easy on the wallet!

 

[Thomv]

If electric fuel pumps on boats are anything like cars you should be able to simply turn the key on for a few seconds before actually cranking the engine over to fully pressurize the system.. Once the engine is cranked any trapped air would be displaced within a revolution or two. Are both pumps powered by the same relay?
Or perhaps they share a fuel pick up that became clogged and the tow and drive home dislodged the blockage?

Both pumps are independent of one another. As I turn each key I can hear each pump energize. I am still going to check and see how each fuel line is hooked up to both motors on Saturday.

 

[Thomv]

On Saturday I actually was able to locate the fuel lines going to each motor from the back of the tank. Both lines are independent from one another. I decided to also check the sending unit. After removing the sending unit I could see there was about half a tank full of gas so I obviously did not run out of gas. I will change both water separators. I still have not been able to replicate the same scenario with the boat still on the trailer. I need to find out what safety feature or fail safe that would cause both motors to start up and then stall within 1 to 2 seconds of firing up. The one thing I am not sure of is when this problem occurred I was at a dock with a band playing so I was not able to hear if both fuel injection pumps actually turned on. Any hepl tryting to figure this situation would be so very helpful. To take some of the anxiety away me and my son will be signing up for Sea Tow.

 

[dubs283]

the water separators would not drain on their own, it sounds as if you have a fuel supply issue - not a bad idea to check the fuel tank pick-ups

the only other thing i can think of is the safety lanyard not in place, it will let the motors run while cranking, then they die when the key is in the run position

 

[Thomv]

the water separators would not drain on their own, it sounds as if you have a fuel supply issue - not a bad idea to check the fuel tank pick-ups

the only other thing i can think of is the safety lanyard not in place, it will let the motors run while cranking, then they die when the key is in the run position

I did check the day it would not start and both lanyards were in place. How do I go about checking the fuel tank pick-ups? When I was removing the sending unit to see if there was gas in the tank which did have half a tank of fuel I did see where both gas lines were connected to the top of the tank, What should I look for at this location?

 

[dubs283]

there is a barb anti siphon valve where the fuel line attaches at the tank

the valve threads into the pick-up assy, which is threaded into the tank

remove the lines, valves, then the pick-ups

also a good idea to check the tank vent line too

 

[Thomv]

there is a barb anti siphon valve where the fuel line attaches at the tank

the valve threads into the pick-up assy, which is threaded into the tank

remove the lines, valves, then the pick-ups

also a good idea to check the tank vent line too

Will do this weekend.
Thanks