change the oil NOW or you can kill the engine with the oil contaminated by the fuel...

Yeah and depending on how contaminated the potential for blowing of the oil pan is there...

Are you guys playing "Jeopardy"?

BZZZZ "Alex, I'll take common marine engine performance issues for a thousand." :D

Speaking of which, the other night I had this vivid dream that I was on Jeopardy, and boy was I cleaning up. I was beating everyone to the buzzer, tallying up thousands in winnings, and then poof, I woke up and realized it was just a dream. The kicker was that the "buzzer" that I was hitting was my snooze button, I hadn't won anything, and I was late for work to boot! So goes my life...

Is the other engine running well? How hard would it be to pull the other carb off the good engine and slap it on there to see if it clears up the problem. That would possibly rule out a ruptured fuel pump diaphragm sending fuel up to the carb.

Absolutely hysterical !!!!!!!

If it has been sitting for a couple of years replace ALL of the fuel lines. The Ethanol in the gas is VERY bad news for any rubber gas lines. Make sure that you get at least a 1/2 dozen fuel filters and don't be shy about changing them. Oh and try to flush the tank REAL good. If you can, cut an access hole in the tank to gain access. Then seal it real good with a cover plate. I have done that to my alum tank and clean it out every fall.

Carbed Gen V 502 had Webers on them. If yours does can them & get a pair Of Holleys. I went thru the same problems you're having. Good thing is you'll burn less gas with the Holley Carbs and better all round performance.

Years ago when I was in high school I worked for a mower repair shop. We had a crappy old Dodge pickup as our delivery vehicle. The carb needed to be rebuilt and would regularly flood the engine. One day while trying to start it, I heard a loud bang under the hood. I jumped out, popped the hood, and saw shards of plastic all over the place. The fumes had made their way up the distributor shaft and ignited under the cap, blowing it to smithereens.