no power at dash engine fires but dies when ignition released

[gsysps]

I have a fairline mirage with twin Volvo Penta 3.0GLP C Serial numbers 4202141659 and 420214160

I have had over heating trouble with the starboard engine but that is now resolved. Until this week the port engine had been fine but now is causing problems. It turned over fine and fired up but as soon as the ignition switch was released into the normal run position the engine cut out. It did this many times. (The starboard engine fired up fine).

The next thing was that the port engine didn't turn over at all. I could here a buzz coming from the "ignition protector" behind the relay. I suspected a drained battery as a result of the failed start attempts. I tested it with a voltmeter across the terminals of the battery and got 9.5 V so swapped batteries. That resolved the no turn over problem but still the engine wont stay running once the ignition switch is released. (My boat doesn't have a kill switch).

I have now noticed that even with a good battery on there is no readings on the port engine gauges. I don't know if that is a subsequent fault or if it occured at the same time as the engine first playing up. My son was starting the engines the first time the port engine played up so I didn't see if the guages were working then or not. The starboard engine gauges all work fine.

I'm thinking an ignition switch or coil problem. (The Boat was rewired before I bought it and all the wires on the ignition switch are red and other than the main harness most other wire colours no longer follow the wiring diagram colours. )

Any help or advice would be most welcome

 

[Don S]

Re: no power at dash engine fires but dies when ignition released

I'm thinking an ignition switch or coil problem.

Ignition switch, possibly, coil- NO way.
If the coil was bad, it wouldn't start at all.
Without color codes, it's going to be tough to tell you what to check.
With the key in the run position, you should have power to the ignition terminal on the ign. switch. (should be purple and go all the way to the coil) if you don't have power to that wire, replace the switch. If you do have it at the switch, find out where it stops. Like I said, it should go all the way to the coil.

 

[gsysps]

Re: no power at dash engine fires but dies when ignition released

Many thanks Don. I found the purple wire (no voltage) but voltage at ignition switch (red cable) was fine. Tracked the two and found a connection break in the line. Fixed and all working now.