Welcome to BGW Answer to your question !!! Look at the line from the tank to the flywheel or front of the engine and you'll see the oil pump then follow the line coming out of the pump and it will go to the top of the carb intake with a banjo fitting. It will be on top can't miss it. The pump is supposed to mix the oil with the gas as it is running a non mix at this point in the tank (Straight gas) Now comes the problem when they work all is good but when the pump fails then goes the engine. Most all of us plugs the line at the intake where the banjo fitting is located and mixes our fuel at 128:1 or 1 oz per gallon then you know you have the proper mix. You can then remove the oil tank and pump and lines and free up room in the engine area
I'll look at the rest of your post and see if I can help.
LOU