Of Course it could. I guess you did say in your first post that you had a 500 HP carb and not a carbed 500 HP.

See post #8 but look at vacuum at idle vs power valve opening vacuum.

I have a vacuum/boost gauge but Vic Jr doesnt have any vacuum ports so I have to drill and tap for one. Guess thats my next weekend project ..

power valve would have no effect on gas leaking in thru tubes, has to be fuel level rising after shut down, either fuel pressure, needle/seats, floats, etc..power would leak thru baseplate....Rob

thanks Rob..

My 850s both had the black floats and the epoxy that holds the weights in came off and the nedel and seat got cloged this year put metal floats in I beleve it was a fuel problem.
Rich

Rich,before rebuild we did pull some unexplained crap out of needle and seat which was weird considering fuel filter was clean.