Why do MSD ignition boxes go bad?
 

So I am most likely going to run the msd ignition on my new motors for just one year. I assume the reason why they are so u reliable in the marine world is the vibration when they are mounted right to the engine. I was thinking about using the rubber mounts and then making a bracket and mounting it to the boat under the gunnell. Thought? Comments?

IDK, Teague uses MSD 6M-2L Ignition Control box and its mounted on the front of the engine.

Daytona sensors

This is exactly what I’m in the process of doing. I tend to agree with you in the vibrations and I’m mounting my boxes with isolation mounts. Time will tell.

Quite often he runs a second redundant system as well, at least in the pics I’ve seen.

I’m going to running the Holley hp ecu for the ignition next year. Just trying to get by for this year.

I mounted my M6 box on the transom and have nothing but flawless performance to report since 2013. I see offshore race boats all the time with MSD boxes under the hatch.

I use MSD in 2 boats (3motors) for years now. One is mounted to the transom 1/4" thick rubber washers between them. The other 2 are mounted to the motors (by a little home made shelf). I do use the MSD 6T # 6400's which are made for circle track racing. The capacitor and transformer receive additional bracing, and all of the circuits and components receive an extra-thick coating of Humi-Seal, to give even more vibration protection (from Summit Racing). All I know is they work.
On a side note, I buy mine on eBay used. I don't care if they work or not and then send them off to the factory. For like 80 bucks they totally rebuild them to brand new inside, they use your old box.

I have my 6M-2L boxes mounted on the transom and have never had a problem. Seven seasons and 500+ hours. Can't say that for the MSD distributors or the coils though.

I had one go bad and it was mounted on rubber isolators away from the engine.
MSD = might suddenly die.