Mercury 150 EFI Help!!

keebs

Cadet
Joined
May 23, 2010
Messages
12
I have a 1998 Mecury 150 outboard with a shutting down problem. It is the EFI (electronic fuel injection) model but must have been one of the early ones as does not have a ECU module that you can plug a diagnostic device into. That is the best model description the mechanic could give me other than to say it has a Power Pack.. (If there is a better way to explain it please let me know).

The problem is the it completely shuts down when running at various speeds. The boat slows down quickly and I shift to neutral and it restarts immediately. This process repeats itself as much as 5-10 times in an hour.

The mechanic has replaced the ignition switch and cut off switch. We also have tried a separate gas tank and line but the problem continues. The mechanic has " wiggled the wires in view while running engine in the shop to try an identify a short but so far no luck. The engine has only been in fresh/brackish water and has very little corrosion on it and looks like new. The mechanic seems to want to now look for broken wires.

Are there any ideas out there?
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,931
Re: Mercury 150 EFI Help!!

Hook a fuel pressure guage to it and run it, when problem occurs check the pressure if low or falling the high pressure pump is failing or running out of fuel or driver in ECU. Replace the manual fuel pump diaphram first and retest, if still shuts down check inlet needle in VST tank and filter on fuel pump. Post the results....
 

kfoss001

Cadet
Joined
Jul 3, 2008
Messages
6
Re: Mercury 150 EFI Help!!

I had the same problem with the same engine...I ended up pulling off the ECM and just sent it to California today for testing. Here is where I sent it.

Simon Motorsports
434 Feghali road
Ramona, CA 92065
760-440-9334

Let me know how you make out or if you find something different out.
 

keebs

Cadet
Joined
May 23, 2010
Messages
12
Re: Mercury 150 EFI Help!!

I had a buddy that switched the ECM on my boat with his ECM, and my boat still was cutting off..
 

keebs

Cadet
Joined
May 23, 2010
Messages
12
Re: Mercury 150 EFI Help!!

Put a voltage regulator on it today and the mechanic is going to take it out this afternoon..
 
Top