1996 Merc 150 EFI issue

[Hoytlifer]

I have a 96 merc 150 efi on my 96 Ranger 461. Thursday sept 14 the boat wouldn't start right off the trailer. Let it sit 15 min and it fired right up and ran well for the 4 hours I was out. Starting and stopping constantly with no issues. Soooooooooooooo! Saturday morning, tournament morning, it would not start. It turns over just fine but doesn't even sound like wanting to fire. 6 miles on a trolling motor makes for a long day! Anyway, the boat has started for 2 years perfectly since I've owned it. It has a new cranking battery this March, new plugs, and I use fuel additive faithfully. New fuel filter last fall also. Any advice would be appreciated before I start throwing unnecessary parts into the motor, thanks.

[JOE54]

see if you hear fuel pump running when key on should run for bout 30 sec

[Hoytlifer]

With cowl off I don't hear pump running.

[JOE54]

possible ecu pump driver bad , you can test pump with jumper wires and check voltage at terminals on pump= no fuel no start

[Hoytlifer]

If I hook to power on fuel pump and then ground it, pump runs and boat will start right up. So bad ecu I'm afraid

[JOE54]

yup

[KevinM]

My buddy had a ECU go out on a similar motor - maybe you can find a good used one

[Hoytlifer]

It's only an $1,800 part! Wooooof

[JOE54]

new one most likely no longer available

[Haughton]

Had mine repaired by http://www.simonmotorsports.com/

Mine had bad fuel drivers and bad map sensor, they repaired and tested it.

[jcronebassmaster]

Take the cowling off the motor and have somebody sit at the console, have them turn the key to on, there is a 1" plug on the right side of the motor if you are standing behind it. wiggle the plug and make sure that it doesnt have a bad connection. I had similar problems and after spending 2 grand on parts i was told to check that and i ended up hard wiring that instead of having a plug and I have had zero problems since

[revlimiter]

If it is the ECU you can always just wire the pump to key on power to get you back on the lake.

[JOE54]

^^^^^ sho could

[Hoytlifer]

That's exactly what I did

[Rich Z]

If it is the ECU you can always just wire the pump to key on power to get you back on the lake.

Yes you can but dont use the purple accessory wire. Not design to handle the amperage draw of the fuel pump.

[EuropeanAM]

BEST to have the drivers replaced... one good option was shown above.

When the driver drops out... it's the GROUND that is missing (not the power side). ECU "modulates" the ground to the fuel pump.