If you want to check the quality of your fuel, disconnect the fuel line from the carb and pump it into a clear bottle. If the fuel has water in it, it will seperate and you will see the problem.

I had a situation like you're describing and it ended up being the battery switch. I replaced it and it was fine. Theres copper contactors in there and they can wear/tarnish/intermittantly fail to deliver ignition spark. Click it on and off a bunch of times and it might make better contact. It's worth a try and I hope you're problem is a simple one.

I had a similar problem. Boat was running fine and then put away for a week. Next time out it was running like chit and wouldn't idle. Plugs were all fouled and it was missing and popping.

Changed plugs and then wouldn't fire. Only had a weak intermittent spark at the plug. Put in an old spare coil and it fired up just like new.

coil

I've got a spare coil, why I didn't check that last weekend, who knows.
I'm going forth and changing plugs and repacing the coil this weekend.
Will let you know how it turns out.

Thanks,

Scott

Coil is the correct answer.
Popped in a replacement spare I had and, along with new plugs, it is running great again.
just in time for Memorial day!
Wonder what will be next??????

Thanks to all.