Pulling a plug wire of is a good way to check, but also a good way to get a good kick in the shorts if you're not careful.
One step at a time buddy, you'll get it. If the plug wire trick shows one not firing then the squirt trick I mentioned can tell you if it is a fuel issue. If adding fuel doesn't get the second cylinder firing then you will have to check spark. You can make or buy a spark gap tester and check each wire to see that you get a good strong bright blue 7/16 long spark off of each wire. If pulling the plug wires off bogs it down equally then you'll know it is firing on both and you can give it a try. I'm gonna check at my buddie's shop tomorrow and see if the trim tab missing is a big problem. I'm kind of thinking if you can handle the steering torque it will not be a big deal. I'll try to post tomorrow (Wednesday) evening from work what he says.
I also think that if you could get a good hole in the busted off bolt and tap it 1/4-20, a 1/4-20 bolt and a flat washer will probably hold the trim tab on for 20 or 30 years. #7 is the recommended drill for a 1/4-20 thread but you might want to go a little larger because you are trying to tap that hard bolt. I think I would try a 7/32 drill and 1/4-20 tap and if you can get a decent thread in it bolt the trim tab on and go boating. The 7/32 will give you a hole about .015 bigger and will give you about a 60% thread, but you'll be a lot less likely to break the tap off. Try to drill the hole as straight and deep as you can and then lube the tap up good wd-40 or pb blaster. If you already have a bigger hole than that let me know how big it is and we'll figure out a thread you can put in it. You don't HAVE to have the 3/8-16.
Make sure you get a good sharp drill and let it do the work. Running a good drill into a banged up hole is a good way to make it dull, so you may need more than one. If it is making chips it is cutting, don't rush it in that hard bolt.
On your solenoid, try a thin single strand (or 2) of copper wire straight into your suspected stripped out plastic hole. You may have to strip a piece of stranded wire and cut a few of the small diameter strands to get wire small enough to use. It will fill in a little space and let your screw get a bite, if it works snug them up and quit. I'll also check on a used solenoid for you tomorrow. My friend has a pile of donor motors. I know he has a blown 110 that has the solenoid if it is still there.
The boat trip to the island and the overnighter on top sounds like a blast.
