Engine just quit.

[Chemdawg]

Hello everyone. So today we were out on the lake, and the wife and I were doing a run at about 32 mph. All of a sudden the motor just stopped. Kind of thought it locked up at first. Once it stopped, I tried to restart, and it turned over very slow, but then started. Ran fine. Put it in drive, and it moved at about 10mph with no problems, and then it did it again. At first I was experiencing vapor lock, but then I thought about it, and was wondering if there was something in my outdrive lower end that could be going bad. Got my boat home, and put the rabbit ears on and it fired right up in the driveway. Ran it for a little bit and put it in gear. I used my metal probe and headphone setup, and touched around the outdrive, and I heard nothing out of the ordinary. No grinding nothing. So it's leading me to believe that it's possibly not in the outdrive.

Any ideas? Anyone had this happen? Motor just stops running like it locked up? Motor runs fine. Im lost.

 

[Rick Stephens]

Sounds electrical. Start with taking apart and wire brushing connections likely to cause ignition issues. Don't forget the lanyard switch, if it has one. Battery connections, especially the ground at the block. Hope the issue is a connection, otherwise hunting an intermittent fault in an ignition component can be tough.

 

[tpenfield]

I had this happen once (well twice actually) but it turned out that I ran out of gas .

I agree with Rick that it sounds electrical . . . wonder if the alternator is becoming intermittent and you are loosing voltage while running.

Another possibility is fuel flow, like maybe the fuel tank vent is clogged.

 

[Bondo]

Ayuh,.... What motor,..?? What drive,..??

 

[Chemdawg]

Thanks for the replies. Once I actually sat and thought about it a bit, I was thinking. It can't be the outdrive. When it dies, it turns over VERY VERY slow almost like a dead battery. I have two batteries, so it's not that. I really thought vapor lock. Checked out my shutters in the exhaust, and that's fine. So it's not water coming back into the motor.

Now I pulled a plug and I noticed it's black and sooty. Rich. But I'm not sure that's a carb adjustment or something else. Since I rewired the whole boat myself, I'm very well versed in the ignition and wiring. I'll be going through that over the weekend.

Bondo. The motor is a 3.0L Mercruiser with Alpha one outdrive.

 

[NHGuy]

If it does that again while running, drop you anchor. Remove the plugs, disconnect the spark and crank over the starter to see what comes out of the plug holes..
You are getting some kind of hydrolock.
It's fuel or water. We need to know what you get.

 

[stonyloam]

Black and sooty says rich. Check the clear line going from the fuel pump to the carb to see if it is full of gas. If you ruptured the fuel pump diaphragm it could be pumping a lot of gas into the carb through that line (which is normally dry), and not be delivering enough gas to keep it running at high speed.

 

[aspeck]

any knocking sound when this was happening? The fact that it turned over very slowly sounds like compression related ... maybe too much fuel or water in cylinders to allow them to compress and turn over ...