I would suggest contacting carburator-parts.com which is Mikes carburetors. They will stand behind the parts and offer the info to find the right one
I also found mentioning 75004-1 at sussex marine
A 1994 should be a carb
Take a 5 gal gas can and maybe 3 to 5 ft of gas line. Disconnect the line from the tank to the fuel filter. Attach hose to fuel filter and stick the other in down in the can
Not sure but think most are in line under some insulation. To check, use a ohm meter and see if you can get continuity from ALT to relay and Start assist relay to fuel pump relay
If its "actually" been winter/summer then it gets ran and has at keast been run on 4 year old gas. That said it could also be there taking his money and not doing the work.
If the drive is in the up position then boots need replaced, not that it wouldn't be a bad idea to do it anyway. Open...
Don't have the GL-G but have the E
Choke is powered from a different tap then the pump
Fuel pump relay is energized when the Yellow/Red is powered while cranking
Once started the ALT powers thru the Green wire
Check the diodes
The sensor is under the distributor cap
https://www.amazon.com/B-Ignition-MerCruiser-Thunderbolt-Distributor/dp/B0784MSV3P/ref=pd_lpo_2?pd_rd_i=B0784MSV3P&psc=1
Looks like you might have found the issue with the buzzer. It may be back feeding power
s for the other power issue, I would remove both ends of both battery cables (do mean both ends) and clean them. Then find main power feed for the blower and other items and clean the power and ground
Don't know how much sand was on top the lower half, but it appears sand and water made it thru the pump.
On another thought, what does the engine coupler look like?
Also rotate the drive shaft and verify it does rotate the lower
