4.3 cut out while on plane?

[gtfireftr]

So I was out today to try to figure out if I have an issue.... I was out last week and I seemed to loose rpm, and speed (about 200 rpm, and 2 mph). It was rough out, and I had a load on, so I thought that may be the issue.
Fast forward.... I went out, and found that she was still a bit sluggish....then on plane about 3600 rpm the port motor started cutting out.... it went from 3600-0 rpm, then up to 2000, then just died... I could get it to restart, but then died again....I kind of figured it was an ignition issue... loosing spark intermittently. I had a coil, and ignition sensor, so I changed them one at a time with no change... ugh.... So I limped home on the starboard engine...
I verified that spark was my problem... I got a spark tester and I could see that I was loosing spark and the engine would die....I was a bit paranoid, so I did a compression check....
I think the numbers are ok, but hopefully someone will verify this for me.
#1 170, #2 160, #3 170, #4 160, #5 170, #6 165....
Anyway, I was considering swapping to a gm electronic ignition system and eliminate the Tunderbolt 4....I was getting ready to order this, but I decided to double check everything first.... I found the main wire off the alternator completely disconnected...Well, I didn't think that this could be the issue, so I repaired the wire to the alternator, and low and behold that was the problem..... I don't know why this would cause this issue....
Can someone please explain this if possible......
Maybe voltage drop to ignition system???
TIA

 

[gtfireftr]

Anyone??

 

[wahlejim]

I am assuming separate batteries for each engine?

 

[wahlejim]

Without getting too detailed with specifics, You need a lot of voltage to create a spark. Your ignition system is designed to take 12 volts at start, or 13-14 volts while running, and convert it to 10,000+ volts. You need the proper voltage and amps in order to accomplish this. With an alternator not providing a recharge to the battery, you were not obtaining the proper amount of either, thus not achieving a spark.

 

[wahlejim]

Think of your electrical system as a plumbing system. A bad wire connection, corrosion, etc. is the equivalent of a leak in a plumbing system. You won't get as much output if there is a leak in the system.