Im getting so frustrated with this thing right now!
Little back ground on the boat… 1994 scarab 29 with the original 502mag. Motor was rebuilt about 3 seasons ago when we first bought it from the second owner. It ran great for 2 seasons. Beginning of last season I took it out and it blew apart the sea pump. The motor got hot, not crazy hot but hot enough that now that I've replaced the exhaust the hoses were all melted on the inside. Last season all of a sudden it started not wanting to pull over 4k RPMs and just didnt seem to be running right. We broke it down to the exhaust diverters leaking and blowing water onto the coil, distributor and wires under a load.
so coming to this season i decided to replace the diverters with new Hardin Marine diverters and put new rubber exhaust boots. I also replaced all the plug wires, cap and rotor. Plugs looked good so i didn't replace those.
I got everything replaced, hooked up the water, and fired it up last night.
Started up fine, and idled for about 30 seconds, then it shut down. I started it back up, it fired right up, then shut right back down.

I've been so busy with my landscaping business i've been trying to work on this a few hours a night and was expecting to get it in the water this weekend… i'm so frustrated right now i'm debating on just putting it back in the corner of the shop and giving up!

Can you tell if you still have a spark? if no,

try a different coil then ign module.

Coils should be mounted verticle unless they are offroad type

if you have a spark then look to fuel filter, pump