I`m kind of a shade-tree mechanic and a tight-wad rolled into one. I hate throwing money at problems and they not go away. If it were my boat, the first thing I would do is run a compression check on all cylinders, if you don`t know exactly how to do this, email me and I will explain or ask here and someone will tell you. If your engine turns out healthy, I would start looking at my ignition. Now, there are plenty of parts on your system that could be at fault. Here`s what I would do: For now, stick in a GM HEI distributor and see if that fixes problem. An HEI is an intregrated unit with coil, module, pickup, etc.. all rolled into one distributor. You can ask around, someone probably has an extra laying around to try. The dirt track racers all run them, if you know any of those guys in your area. Or you can get a good used one from the junkyard for about $40, just make sure it is complete with cap, coil, etc... If this fixes your problem, you can run the HEI from now on, just recurve it for your engine. Or buy an MSD distributor from Summit or Jegs. Hope this helps! Good Luck!

Here's the latest...
 

Opened the distributor the other day and inspected the pick-up module. Condition was kinda rusty, so I pulled it. Heading to the local merc dealer now to find a replacement. $80 bones, Ouch!! compression check still needs to be done. How hard is it. I don't have the guages or know exactly what I'm doing. I still need to call on KCHOTBOAT to check the timing... just no time yet (pardon the pun).
It seems that I'm chasing the simple fixes and avoiding the thought that something major has occured. Crazy psychology, I know.
Thanks for the continued interest and keep the ideas coming.
Travis

-check ignition wires-happened to me once.new -out of box but was not working

-same for plugs -but you already did

-ignition timing -!! I think this is the reason
Late July - decide to go ahead and replace plugs and wires (extreme power loss)

hope you find the problem and fix it soon.Good luck!