Fuel fillers are normally on the outside of the boat, so fuel doesn't spill inside the hull. I am not sure why you would want two fill fittings for one tank.
However, a brass Y in 1-1/2" size should work, I would think.
Do what you can to optimize, as was suggested. Pontoon boats are displacement hulls, for the most part. as such, 20MPH is not the best they can do, but is close. My neighbor has a 24' pontoon with a 150HP Yammie. He gets 22mph.
When the orange wires ground they tell the switchboxes to stop making spark. Disconnect them from the switchboxes and test for spark.
If spark returns, check the wiring from switchboxes to ign key for continuity. They should not have any voltage on them and must connect to one of the "M"...
It is probably better if you do not rip the boat apart and patch it for the season. If you rip out the foam and rotten wood, and do not replace it with new foam and properly attached wood, the boat could be weaker than it is now.
Alternatively, you could screw down some new plywood decking...
A lot of sterndrives have a temp gauge and a overheat alarm. Each of those have their own senders. On my MerCruiser, both sensors were in the thermostat housing.
If you proved the gauge sender is good, and the gauge is good, the wiring is likely bad.
Gearcases are tricky to install in forward. I would recommend you turn it CCW back to neutral as you did before. Now tilt the motor all the way up, grease the driveshaft and shift splines and install the gearcase. Turn the flywheel a bit to synch the driveshaft splines, and she should go on a...
As long as the water doesn't freeze, you are OK, with the outdrive down and the block is kept warm. On an I/O, I always put a 40W heating pad under the oil pan whenever the temps got to freezing. I would fish into Jan here on the NJ coast.
However, once you pull it, it needs to be...
I think you need to look for a wire downstream of the circuit breaker, that carries power. It would be a thick wire say 8 gauge, and it would need to rub against the metal of the engine and have a bare spot where the insulation has rubbed off. You might see a burn mark as well.
You will want to ski at about 35MPH, if slalom. With your motor and boat, I would expect a 21P 3 blade prop would work well, and still give 45-50MPH or so at WOT. Turning point makes an inexpensive 3 blade alum prop with good rake.
You likely have slightly different wiring colors than was posted.
Red is battery power. It may be fuse protected and be a red/purple color. Connects to "B" terminal.
Black is ground. Connects to "M" terminal.
Black/yellow is ign killer wire. Connects to other "M" terminal.
Purple is ign...
Maybe the neutral safety switch has a broken wire inside the control, or it is not activating for some reason? I presume you took the controller apart to grease the cables? Any parts left over?
I have a '98 SeaSwirl 2100 DC striper. All of the access to the plumbing components is granted by hatches or one kind or another. So you may need to remove some of the boats components, but I can get to everything necessary. Hopefully your model is the same.
I have thru hull fittings for the...
Gee, what prop pitch and what kind of boat? For extra credit, what is the gear ratio of your gearcase? Have you changed props recently?
Revving up under no load is not relevant. You could ohm out the high speed stator windings.
If the length is good and the conductor is stainless steel, and the terminals and length match, it should work.
I am surprised that Merc did not make the wires available. They are required to carry parts for 20 years, which your motor is that old. There are parts available for a lot older Merc...
OK, the web says your motor was made by Yamaha, and the wires are avail from them or Sierra. Yamaha 18-8847-1 avail from Sierra
https://www.wholesalemarine.com/sierra-18-8847-1-yamaha-spark-plug-wire-set/?avad=220733_d3b9ca8a1
With the reliability of the internet, You might take one of your...
