Long post alert. Read on if you want to learn why I was chasing my tail for awhile. Posting in case anyone else has a similar problem and it is not solved by replacing the air silencer cover gasket.
Crosbyman- Thanks for the documents! Will be helpful if I pick up an older motor without the re-circ lines.
Last year, when I rebuilt the carburetors, fuel pump and replaced all of the fuel lines, I put everything back together, with the original cork gasket. I figured it was the original cork gasket leaking here, so ran the motor with the air silencer cover off (#15 in attached) and saw mixed gas coming in to the box from the nipple in the lower right corner from the crankcase. I assumed this was the ONLY leak and that replacing the cork gasket would solve the issue. It did not. This weekend, I spent several hours cleaning any residual gas/oil around the carburetors , air silencer box, and dried everything completely.
After running the engine, and tilting it up, the fuel seemed to drip from the lower seam of the air silencer box/cover. BUT the lower carb bowl gasket also seemed wet with fuel, which shouldn't happen if only the air silencer cover gasket was leaking. Took the air silencer cover off again, removed the box (#28 in attached) and took off the lower carb to inspect/tighten the bowl screws which already tight. When re-installing the box (#28), noticed the gasket between the silencer box and carb (#46) didn't seem to seal well to the lower flange of the lower carb (circled area on #28). Took the air silencer box off again and checked this mating surface with a straight edge and feeler gauges. The mating surface of the air silencer box was distorted approx. .030" in the center causing #46 to not seal well. This air silencer box is held to the carbs with 2x bolts in each carb on the outside edge of the carbs. Then the air silencer cover is held to the box with 3x bolts in the center, which when tightened, pull out slightly on the center of the air silencer box, directly in the middle of the carb sealing flange gasket (#46).
Was able to support the box at the bolt holes and tap the center area of the box sealing flange straight again, reinstalled the gasket, which was now firmly pressed along the entire carb length, and re-installed the air silencer cover.
Ran the engine several times last night and no fuel is leaking around the air silencer or carbs now! Thanks to everyone who helped me troubleshoot this issue. Think I may have overtightened the air silencer cover bolts last year which pulled out on the air box/carb mating surface enough to deform it (Cast aluminum). Once the air silencer box is installed, this is a very difficult area to inspect. I assumed the fuel dripping from the lower corner of the air silencer box was coming through/around the flange between the box and cover. It was not. When the engine is tilted up, as others noted, the fuel leaks out of the carbs into the air silencer. What I did not think to look for, and you cant really see it with the air silencer cover attached, is fuel leaking between the carb and air silencer box, down the outside back of the box and dripping from the lower flange of the box. The fuel I seen on the lower carb bowl gasket was dripping down the outside back of the air box, and wicking across the bowl gasket.
Thanks again everyone, this is an awesome place for knowledge!
