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Troubleshooting an electrical gremlin.

sintax

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Monday I got the boat on the water and the MSD box took a shit about 2 mi from Windsor. I got it fire for a second, and it ran for maybe 20 seconds and then hard dead in the water. I unplugged the distributor, and tested the box, the box had a very faint buzz, but ZERO spark when jumping the green and purple wires. Towed it back, and swapped the 6M-2 with a new in box 6M-2L (but left the existing harness). This box now tests good, fires right up on the trailer, figured it was good to go the next day.

Put the boat back on the water the following day, everything seems normal, about 20 min into running down to the dam, it dies, lights out. I was running around 4k, just cruising. She fired right back up again, and I decided it would be wise to head back towards the ramp in case this turned into a repeat from monday. I wanted to find a cove to check all of my connections and terminals, so I ran until I found a decent cove, as I was idling in the cove in gear she died again, same manner, just like you turned the key off, but started right back up. I had it happen a few more times throughout the day, but i stayed somewhat close since I didnt have much faith in the boat at that point.

As i see it the following items are in play, I'm open to any thoughts anyone might have as the likelihood of where to start replacing parts.

MSD 6M-2L (new unit, but maybe its faulty?)
MSD 8560 distributor - unknown age, but maybe the pickup coil is failing? I think I can order a replacement coil assembly
MSD Blaster coil - unknown age, but i've never had intermittent issues with a coil. Its usually all or nothing

key switch - seems to be ok, and I BELIEVE i always saw power on my batt volt gauge, but its a cheap replacement
velvet drive NSS - I dont know if these fail, and if so, how? I'd expect it would be similar to a car where you'd start having it not want to start because it thinks its in gear.
remote starting solenoid - I dont know if these fail, and if so, how?
 

LazyLavey

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I threw my MSD box in the trash years ago. after numerous random non starts, I realized when I unplugged the msd and plugged the oem back it its been fine for years .....

I'm stock 454 mag and frankly don't feel any difference with or without the box.

I assume big power engines may benefit with a MSD?
 

sintax

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I threw my MSD box in the trash years ago. after numerous random non starts, I realized when I unplugged the msd and plugged the oem back it its been fine for years .....

I'm stock 454 mag and frankly don't feel any difference with or without the box.

I assume big power engines may benefit with a MSD?

you're not the only person whos told me this. I'm pretty confident I could prob toss an HEI in and be done with it, but it was setup this way when I got it, so I just kinda kept that ball rolling down the road. The engine builder did suggest I ran it when I brought the topic up. Its not a 1000hp engine, but shes pretty stout.
 

LazyLavey

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In my case the MSD box and the other little square thingy with wires looks cool.....lol
 

renodaytona

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How's your voltage from your alternator? I had an MSD die on me going up river several years ago due to low voltage. MSD ignitions like over 12 volts all the time.
 

rivermobster

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Throw that junk in the trash and go with a Pertronix ready to run distributor.

Get the coil to match whatever version you get (Ignitor 1, 2 or 3).

Live happily. 😊
 

sintax

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How's your voltage from your alternator? I had an MSD die on me going up river several years ago due to low voltage. MSD ignitions like over 12 volts all the time.

volt gauge is reading 14 while running, 12 off, so i'm thinking thats ok. two brand new deka 1000cca batts too
 

stoker2001

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I assume you are using the marine MSD,which I believe is blue?to troubleshoot you have to backprobe wires and do wiggle tests while all circuits are under load (use third set of hands if you have too)..never rule out bad connections at plugs and connectors and bad OEM crimps .look for corroded,loose grounds or painted surfaces used for grounds
 

bagged97taco

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Monday I got the boat on the water and the MSD box took a shit about 2 mi from Windsor. I got it fire for a second, and it ran for maybe 20 seconds and then hard dead in the water. I unplugged the distributor, and tested the box, the box had a very faint buzz, but ZERO spark when jumping the green and purple wires. Towed it back, and swapped the 6M-2 with a new in box 6M-2L (but left the existing harness). This box now tests good, fires right up on the trailer, figured it was good to go the next day.

Put the boat back on the water the following day, everything seems normal, about 20 min into running down to the dam, it dies, lights out. I was running around 4k, just cruising. She fired right back up again, and I decided it would be wise to head back towards the ramp in case this turned into a repeat from monday. I wanted to find a cove to check all of my connections and terminals, so I ran until I found a decent cove, as I was idling in the cove in gear she died again, same manner, just like you turned the key off, but started right back up. I had it happen a few more times throughout the day, but i stayed somewhat close since I didnt have much faith in the boat at that point.

As i see it the following items are in play, I'm open to any thoughts anyone might have as the likelihood of where to start replacing parts.

MSD 6M-2L (new unit, but maybe its faulty?)
MSD 8560 distributor - unknown age, but maybe the pickup coil is failing? I think I can order a replacement coil assembly
MSD Blaster coil - unknown age, but i've never had intermittent issues with a coil. Its usually all or nothing

key switch - seems to be ok, and I BELIEVE i always saw power on my batt volt gauge, but its a cheap replacement
velvet drive NSS - I dont know if these fail, and if so, how? I'd expect it would be similar to a car where you'd start having it not want to start because it thinks its in gear.
remote starting solenoid - I dont know if these fail, and if so, how?
We battled an msd issue for 2 races last year in the Cole. We swapped boxes, new coils (yes plural) new distributor , new battery, new crank trigger. Come to find out we had a wire that went to coil that would be fine at idle on trailer but connection would fail under power due to vibration. Sucked trying to find that gremlin We started to rewire everything. Not much on a flat bottom tho.
 

sintax

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We battled an msd issue for 2 races last year in the Cole. We swapped boxes, new coils (yes plural) new distributor , new battery, new crank trigger. Come to find out we had a wire that went to coil that would be fine at idle on trailer but connection would fail under power due to vibration. Sucked trying to find that gremlin We started to rewire everything. Not much on a flat bottom tho.

So i've kind of suspected also something similar. I think the weatherpack connector that connects the DIST to the BOX.
 

sintax

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I assume you are using the marine MSD,which I believe is blue?to troubleshoot you have to backprobe wires and do wiggle tests while all circuits are under load (use third set of hands if you have too)..never rule out bad connections at plugs and connectors and bad OEM crimps .look for corroded,loose grounds or painted surfaces used for grounds

yea, thats going into my next troubleshooting session. I didnt have the necessary ring terminals to shorten and properly recrimp the rings for the power and ground. The ground is attached to the polished alum ski tow, that bolt passes through the ski tow, into the head.
 

rivermobster

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We battled an msd issue for 2 races last year in the Cole. We swapped boxes, new coils (yes plural) new distributor , new battery, new crank trigger. Come to find out we had a wire that went to coil that would be fine at idle on trailer but connection would fail under power due to vibration. Sucked trying to find that gremlin We started to rewire everything. Not much on a flat bottom tho.

Yeah like....

One? Ok, maybe 2.

:p
 

Carlson-jet

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Is there a chart that shows an MSD system increases H.P. naturally aspirated @ 5k RPM?
 

shan

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If you have the removal tool for a weatherpack terminal, remove one of the males and check the tightness in all of the females. They can be/get sloppy and cause intermittents like this.
 

sintax

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If you have the removal tool for a weatherpack terminal, remove one of the males and check the tightness in all of the females. They can be/get sloppy and cause intermittents like this.

yea, i do have a set of those prong tools. I plan on trying to do just that the next time i'm out. This is currently my number one theory.
 

Carlson-jet

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I'm agreeing with you for him to throw it in the trash and KISS.
I run a magneto that is 40 years new. 👍
 

shan

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yea, i do have a set of those prong tools. I plan on trying to do just that the next time i'm out. This is currently my number one theory.
There's a reason the OEMs dumped that connector architecture in the 90s. There are much more robust options available now. I'm helping a buddy wire a boat now, and we will be replacing that connector with a metri-pack.
 
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