Tidal Fish Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
187 Posts
Discussion Starter · #1 ·
I have a pair of 1998 Mercury 250 hp EFI. My starboard side motor starts right up but the port side just turns and turns with not even a hint of starting. Checked the juice at the electric fuel pump and not showing any at all for the port side. Starboard side is showing 11.0 when the key switch is turned on. Is there a fuse or something in line? I only have one safety lanyard switch so it's not that? :help::help::help:
 

·
Registered
Joined
·
993 Posts
You should have at least 12 - 13.5 Volts at the red terminal at the fuel pump. Switch to a fully charged battery and retry.

The fuel pump is operated by a fuel ECM. You have two ECM's on that engine. The other is the ignition ECM.

To test the fuel pump:



Disconnect RED/PURPLE wire to NEGATIVE
terminal on electric fuel pump. Connect a ground jumper wire from NEGATIVE pump terminal to a good engine ground.


Results:

Pump does not operate. Replace electric fuel pump. Pump operates. But, pressure reading does not change when performing electric fuel pump pressure” test. Replace electric fuel pump. Pump operates. Check RED/PURPLE (-) lead and harness for good continuity. NOTE: RED/PURPLE lead is connected to pin 9 of EFI ECM harness.
 

·
Registered
Joined
·
993 Posts
Well, I removed the red wire from the fuel pump and installed a jumoer ground and still no AMP's at the fuel pump. Wouldn't that tend to be the fuel ECU? :help:
The Red is the power to the pump. That wire should have 12V. Leave that one connected. Remove the red wire that has a purple line through it. Connect a wire from ground to the terminal that the red and purple wire were connected to. That should make the pump run. If it doesn't run then the pump is bad. If it does run, then the fuel ECM is suspect.
 

·
Registered
Joined
·
187 Posts
Discussion Starter · #6 ·
Well, jumped the red/purple wire and the pump does make noise but not the same as starboard motor. I am finished messing with it. I have Oaks Marine coming to the house to look at it on June 2nd. Just hope he can fix it and the bluefin are still around that weekend.
 

·
Registered
Joined
·
2,583 Posts
Some of the older EFI fuels pumps did have problems with longevity. If I remember correctly it was $135 when I replaced the one on a 1993 or 1994 150EFI about 10 years ago. It was only about 6 years old.
 

·
Registered
Joined
·
187 Posts
Discussion Starter · #9 ·
Turns out that the problem was a bad check valve at the bottom of the fuel pump. Brass fitting that screws right into the aluminum housing of the fuel pump. Also found a couple broken recirculating lines too. Runs like a top now.
 
1 - 9 of 9 Posts
Top