engine dies

[twag4]

I have a 1999 mercruiser 4.3L w/ gen II and 2 barrel carb. It is in an 18 foot runabout. Today we were on the lake, boat started and ran as normal, pulling kids on tube and skis. We had several instances of the boat running along about 20-25 mph indicated and the engine just died. It would start right back up and ran otherwise normally. We started the day w/ 3/4 tank of gas. It started when we were just a little over half a tank, and we left with 1/4 tank. It seemed to be worse when going from a greater throttle setting and then pulling it back such as after getting on plane. Also it happened more frequently as the day drew on. It did it twice then not again for awhile, got bad at the end--ending the day on the lake. The fuel water separator was new about 6 hours ago, going to do a carb kit and tune up anyway, tune up stuff already ordered. Anybody have an opinion if this should take care of the problem?

 

[getinmerry]

Re: engine dies

Since nobody else has touched this one, I'll give my opinion and others will chime in I'm sure.

You're suspecting a fuel problem from the looks of your post. It's possible that the pick-up in the tank is clogging or not reaching the fuel when you're getting on plane.

I would also consider that the coil might be breaking down and failing when hot. I've had the problem on both boats and cars. Same symptoms as you're describing. Random shut-downs, and usually restarts with no problem.

I think you need to do more trouble shooting when the problem is occurring and gather more information so everyone can help out. Intermittent problems can be a B---- to locate.

Chuck

 

[searay3]

Re: engine dies

Tune up is a good place to start if you haven't this season. I would also look at the anti siphon valve. It is located at the fuel tank on the pick up line. Check the tank vent, make sure the line isn't kinked and it is clear. A good way to narrow fuel tank issues is an outboard 6 gallon attached directly to the fuel pump suction side. See if that changes things. There is also a filter at the carb inlet that could also be slowing things down. I'm sure more will have input.

 

[bamaboaters]

Re: engine dies

I am by no means an expert here. I had a very similar situation that drove me crazy for an entire season. Turned out to be a bad ign coil.

 

[sarantis]

Re: engine dies

I had similar problem and it drove me crazy for long time.Finally it turned out to be the simplest thing.Bad fuel.I would suggest tocheck 1)try to tun with an external tank 2)replace the fuel filter-water separator 3)the fuel filter at the inlet of the carb if ther is.

 

[Bondo]

Re: engine dies

and the engine just died. It would start right back up and ran otherwise normally.

Ayuh,......

That Screams Electrical to Me.........

 

[Don S]

Re: engine dies

The fuel water separator was new about 6 hours ago, going to do a carb kit and tune up anyway, tune up stuff already ordered. Anybody have an opinion if this should take care of the problem?

You can replace all that stuff, and have every thing set perfect, and it will probably do the same thing.
Read this thread.
http://forums.iboats.com/showthread.php?t=167561

 

[twag4]

Re: engine dies

thank you all for your replies. I have my work cut out for me and I look forward to fixing the problem. Don S would the fuel problem cause it only to cut out when reducing throttle from a more open setting? I originally told my wife either coil or some sort of fuel problem, but until you replied I convinced myself that it would be worse with throttle at constant setting and higher settings. I am definitely going to do the tests that the thread you gave indicates.

 

[twag4]

Re: engine dies

Well, after many weeks trying to isolate problem when I could get on the water, I finally connected the two wires going into the oil pressure switch that controls the fuel pump bypassing the switch, and problem quit. I made sure not to have ignition on, fuel pump would run otherwise, and it never stalled again. New switch in today, installed it, problem solved. Four hours of skiing and tubing and all is well. Thanks for all of the ideas iboats crowd!