Engine Starts and Immediately Stalls

[canuckkb]

Greetings,
It has been a while since I have been to this forum because of a change an career and location, however it is finally time to get back at the boat. Anyways, I have a '76 tri-fly with twin chrysler 400s. For some reason, I am unable to start the starboard engine from the lower helm. From the upper helm, it starts and purrs like a kitten. From the lower helm, it starts right up and then immediately stalls. It has been doing this for a couple years now. I had a mechanic look as it, and he stated that the tach was faulty. At the same time, I had the ignition changed over from the original Chrysler to an MSD Ignition pack. Later on I swapped the tachs around and found that the issue was not the tach. Anyways, I would like to fix it because I prefer to start from the lower helm so that I can hear the engines. Does anybody have any thoughts on this.
Thank you.

[The Dog House]

Maybe the neutral safety switch on the lower control console?

[canuckkb]

Thank you for the fast reply.
I did not know that it has a neutral safety switch on the lower control. I will take a closer look. Maybe I looked right at it and did not see it.

[mikeandanne]

Sounds like the run side of that circuit is not staying in.....have you tried a new switch or try one you know is good ?.....used to be that would indicate replacing the ballast resistor....not sure how your new stuff is wired, but you should check for voltage with the lower helm ignition switch in the run position..start there.

[prowlersfish]

Sounds like the run side of that circuit is not staying in.....have you tried a new switch or try one you know is good ?.....used to be that would indicate replacing the ballast resistor....not sure how your new stuff is wired, but you should check for voltage with the lower helm ignition switch in the run position..start there.

Agreed , I would start at the switch

[Big D]

Sounds like the run side of that circuit is not staying in.....have you tried a new switch or try one you know is good ?.....used to be that would indicate replacing the ballast resistor....not sure how your new stuff is wired, but you should check for voltage with the lower helm ignition switch in the run position..start there.

+1
That's where I would start. Does it quit as soon as you let go of the key? If so, sounds like the RUN side of the switch is defective. If you're good with a meter, it's an easy check.

I suspect the neutral safety switch is on the tranny. It must be something that is isolated to the lower helm. Check the wiring harness plug at the helm as well.

[Christian]

I have the same issue. One thing I did notice though is that if the neutral switch is active, the engines will not turn over. My engines do turn over but depending on where I try to start the engines, they keep running or die. Currently, what I do is: turn the power ON in the lower helm then go to the fly-bridge and start the engines from there. problem with that is that you can't turn off the engines from the fly-bridge. I have to go back down to the lower helm...

Christian

[canuckkb]

I guess that i forgot to add that i did swap the ignition switches around and that the problem stayed with that side, and did not follow the switch. The other thing that i forgot to mention is that the buzzer on this engine does not sound while starting. I am not sure how this is wired or is this would have anything to do with the problem.
In a hour or so, I will jump up on the boat and try a few things. If it reacts the same way as Christian's (turn the power ON in the lower helm then go to the fly-bridge and start the engines from there. problem with that is that you can't turn off the engines from the fly-bridge. I have to go back down to the lower helm...), then I think that tells me that the run side of the switch and the wire to the engine are good. Maybe. While I am at it, I while try to trace the wire for the run side. There must be a connection somewhere. At the helm the wires are yellow, however at the engine they are all color coded.
Christian, if I discover anything, I will be sure to let you know.
Thank you
Kevin

[canuckkb]

So I found the issue that was causing my stalling problem. With the access panel to the back of the guages removed, I was able to trace the wires from the ignition switch. The "run" wire was broken, just as it entered the wiring harness. It was difficult to find, but easy to fix.

A side note. Last year I was having stalling problems with this same engine. It would run beautifully for a while, then stall without any kind for warning, and would not restart for what seemed like hours. I was bobbing around on Lake Huron and I found that he fuel/water separator was empty. I just happened to have an electric fuel pump on me, so I quickly installed it. The engine started right up and ran great. The next few times that I used the boat, this engine would again stall with warning, however it would restart with pumping the throttle and revving it up. Today I was checking gas line fittings and connections. Close to the tank, I found a fitting that had evidence of leaking, and two other fittings that were fairly loose. I am guessing that the fuel pump was sucking air from these fitting. Hopefully I am right.

Thank you for your help.
Kevin

[Big D]

...It would run beautifully for a while, then stall without any kind for warning,.....

Usually when an engine simply quits without warning like running rough or caughing first, it's typically an electrical/ignition circuit related problem. If it runs rough then quits, it's typically a fuel related cause. There are exceptions to everything of course but it's a good rule of thumb to get you focusing on a particular system until you can rule it out completely.