Bypassing MSD box to get home
 

Lost a MSD box Saturday. Put the old crappy spare I had in the boat on only to lose it moments later. Ordered two new ones from Jegs and will keep the other one as a spare. Talked to MSD about possibly rebuilding the old ones but they say the marine version is epoxied and can not be disassembled.

Anyway, I was thinking you could probably run a bypass through a switch and if one failed you could flip the switch and make it home. You wouldnt have optimum spark but it would keep you from limping in.

First boat with MSD and learning that it's not uncommon for them to fail......

what kind of distributor are you running ?

don't see why guys try to run these things on boats, except for the rev limiter(which can be done alone) you don't gain squat ! and then have to deal with issure like this....MSD=may soon die....I have to run their high tech digital stuff on my top sportsman race car and hate it..but I refuse to in my boats..

I'm running the 6460 MSD boxes, MSD rev limiters, MSD Blaster coil, and MSD distributors.

I wouldnt be running it on a stock setup. I asked my mechanic if I could just lose them but the motors are pretty radical so he said it would be better to leave it all in place.

I will say this, its like a ball of fire on the end of the plug. No weak little spark. I can't imagine getting shocked by one. It would probably be like getting hit by a tazer.....

Depends on the setup. Points with mechanical advance or Tbolt IV distributor and module can bypass the MSD.

Well, found the issue last night as to why the boxes went, or at least I think. The bolts that hold the rear housing on the alternator had come out! Basically behind the mounting point it would spin only stopped by the wires. First time I've ever seen or heard of that happening. No telling what kind of crazy voltage was going to the boxes.....

Dropping alternator off for a rebuild today. Hope to be back on the water by tomorrow.

well if you are running pro billet dist you cannot by-pass to get home, only stand alone dist will work with that...I'll make a bet with you drop in a cheap H/P hei bet you will run the same....

Voltage drops will kill the boxes fast. Seems the marine ones are more suceptible. Make sure you run a short, big 12 V supply to the box.

I'm pretty sure your box failing is because you drive like crap. I'm just sayin' :evilb: :ernaehrung004:

I'm 99% certain that MSD distributors require MSD boxes to run. At least they did in '98 when I was running them on my race car.

they should run with the 12$ "blue grommet box" from any parts store.

if it is one of their "ready to run" dist then the box can be bypassed to run without...

For what it's worth... I had a boat with 500 EFIs in it that had the marine MSDs on it. However, the man that had installed them had done it in such a way that it retained the factory ignition, and by swapping a pair of 2 wire connectors on the back of the motor you could go back to the factory Merc stuff. Saved me once when one of the MSDs took a crap. Alexi and BoostPower set them up that way, so I'm sure if anyone had a question as to how to do it they could drop him a line.

Quit posting on here and get back to work on your boat. If you spent as much time working on the boat as you do posting you maybe could have been on the water this weekend.

Well, put a new alternator on and new MSD box and the boat ran perfect. The boxes blowing were only a symptom of the real problem. I would recomend to anyone that blows a box to check their voltage both on the main power wire (big red wire) and the keyed hot wire (small red wire) before putting a new box on. Probably would have saved me a MSD box. MSD says any significant difference in voltage in the two wires will blow them.

Important part is I'm back on the water!:drink: