So I took the boat out this weekend, started great, idled fine, went to get up on a plane, at about 3000 rpm the engine died, and wouldn't restart.. towed back, and had a look in the driveway tonight. Getting no spark at the plugs. I tested this by pulling a plug wire, throwing an old plug in, grounding it against the head, and getting no spark. Next test was the msd 6m-2 box. I did the recommended test with the screwdriver in the coil wire, near a ground , and got a healthy spark jump to my ground, by jumping the green/purple wires in the harness to the distributor. To me, that eliminated my Ignition box as the problem.. where would I look next? I've never had an issue before. Grounds are good, the boat ran great for a few weekends before this with the bed engine installed. The one thing I did test and notice tonight, was the 12v power wire for my msd box is jumped from the starter power, and that battery was only showing 12v on my mulitimeter, while my other battery was up at 12.7. It appears they forgot a jumper cable to bridge my 2 batteries. Would the battery being at 12v be the cause of this ignition issue?

I don't think 12 volts would be a problem. The heavy red& black wires should go to the battery. Check the pick up coil in the dist.

i agree.

You said the grounds are good. Are you assuming that or did you actually remove them and clean the contact surfaces?

i tested the ohms on the harness coming out of the distributor and am getting 590 as msd says I should , which SHOULD eliminate that problem as well...

yes. Checked and cleaned grounds.

For schits and gigles, fully charge that battery and try again. Even though I have ran MSD's on vehicles without alternators down to 10 volts or so, I do know MSD's can be cranky pants and do some weird things.

I chased all sorts of problems with mine last Summer and followed MSD's trouble shooting tips etc. We thought it was a bad battery, bad coil, bad ground, alternator, ignition switch....ended up being the box after all. It was odd as it would act up some days and not others so it was difficult to diagnose. As many will tell you it is not a bad idea to carry a spare and before wasting all Summer may be worth it to swap it out.

MSD's should come with Sea Tow membership.

Got two crane boxes I swapped out for my Daytona boxes . Work perfect. Wanted the added benefits of the daytonas. But fell short on the downloading. Ended up a 750 he programmed curve. Waste of money .. but maybe down the road.