problem with Merc 150 EFI

[muskyfever]

My 1994 Merc 150 EFI will just cut out on me whether I am idling slowly or full speed. It's like the dead man switch is used, it's that quick. It always starts right up again without a problem. Had it in to the dealer last fall and of course they could not duplicate the problem. Anyone out there have that happen before? Any suggestions besides buying a new motor? Thanks

[PerchJerker]

Some optis have had issues where the pins inside the electrical connectors get bent or mushed, the mechanics will straighten or spread the pins and use dielectric grease to ensure a good connection. Not sure if that's what's going on with your motor, hopefully your mechanics would know about that.

[BoxMN]

Do stators go in and out? I don't think so, I think if they are bad they are like a dead lightbulb, but if it just plains "stops" that sounds like what happens when a stator is out.

Did you check the super easy things, like good connections to battery and the motor?

Good luck, wish I could help you. Our 97 is so far so goooooood.

[boatfixer]

Those types of problems can be difficult to pin point. It could be the kill switch, safety switch, poor connection as PJ mentioned, power to the injectors, it could be the ECM. It's just tough to put a finger on it.

[hydro]

It might be a fuel delivery issue as well. I had the same problem (1999 200 EFI, non "opti")and I found a loose threaded fitting that allowed air to be sucked into the fuel stream. Once the fitting was resealed and tightened the problem has not recurred.

[ChuckN]

I have a '94 175 EFI Merc, and I did have a similar incidents last summer. It usually occurred on hot days. My only guess was a fuel delivery issue, like vapor lock. The motor would suddenly die at all RPMs....full throttle, idle, but I had to pump the bulb a few times.

Do you have to pump the fuel line bulb to start it?

I never did anything about it since I noticed it only happened on really hot days.

I haven't had a problem this summer.

[taw]

Sounds like the voltage regulator which supplies power to the fuel pump. My 1997 EFI did the same thing and the boat mechanic I use told me this was a common failure in Merc EFI motors.

[muskyfever]

Thanks to all of you with your suggestions. This is a difficult problem to nail down and all of these suggestions will help when I take it in to the mechanic again. Musky Fever