Volvo Penta 4.3GL spark issue

[West Islander]

First thank you all for your expertise and advice, I frequent this site to get information but I have never posted before.... I have a 2000 Sea Ox 223F walk around with a Volvo Penta 4.3 GL (carbed with EST ignition). The MOB tether switch was deleted on this boat by a previous owner. The starter had acted up on the boat so I had to rap on it with a hammer to get it to turn over recently.

The other day I was on the water for a full day, the boat was running fine, idling fine, cruising fine, and (occasionally) topping out fine. At the end of the day we were headed home and decided to stop to take a few pictures. As I eased the throttle back from a cruising speed the engine sputtered and died. It has never done this to me before. I tried to restarting and it cranked but wouldn’t start. I guessed I may have a clogged fuel filter so I swapped it out with a new one. I cranked it over and it still wouldn’t fire. I did get it to briefly run only when I sprayed it with starter fluid. Long story short I had to get towed to port.

still convinced it was fuel I disconnected the fuel line at the Carburetor, plenty of fuel. Looked down the throat and it was shooting plenty of fuel. I removed spark plug #1, grounded it, and cranked. No spark (By now the batteries were low, but The engine would still turn over). Next I checked to see if I was getting spark from the coil. Nothing....

I towed the boat home and hooked it up to a battery tender for a few nights. I did some research where I determined that I needed to check the Purple wire at the coil with the ignition on to see if I had 12v at the coil. I pulled the lead and expected to see 0v (by now I believed when I hit the starter with a hammer that I had damaged the purple wire from the starter to the coil and that is what caused the failure) I was surprised to see that I had 12.76v at the coils purple wire. So I tried staring it and the engine immediately fired and ran smoothly.....:grumpy:

now I don’t know what to think and am seeking guidance.... possibly a ground issue? The only ground I saw in the schematic is the coil itself being directly grounded when it’s bolted on. The MOB delete was still intact (the 2 leads to the switch crimped together with no corrosion issues).... any advice would be greatly appreciated

 

[alldodge]

There isn't a purple wire by the starter
Need ti=o find out what becomes disconnected.

So if you loose power to the purple wire then its the kill switch or the key switch

 

[West Islander]

I posted a couple of pictures, one of my starter and the second of a schematic I found. I know that the schematic is for a 5.0..... is the 4.3 different?

 

[dschnacky]

West Islander here is a wiring diagram for a 4.3 GL-G(F)

 

[alldodge]

Upon seeing the pic of your starter I would guess you have corrosion issues. Disconnect the battery and then take the cables off the starter and clean them up. The hitting the starter with a hammer trick jars it enough so the cables can pass enough power. If they get cleaned up to shinny metal this will probably go away

If it does it again, have a voltmeter with you. Start with measuring voltage at the coil, and if its low or zero, check the kill switch (MOB). Might turn it on/off to see if that is the issue.

There are probably other places where corrosion has built up so need to do some maintenance

 

[West Islander]

Thanks for the advice, today I checked / cleaned the grounds at the engine and plan on doing the same at the starter. Thinking ahead to if this happens again, if I carry a wire with alligator clips I could supply the coil with power directly from the positive battery terminal and limp home correct?

 

[alldodge]

Yes, IF the issue is you lost power to the motor