If you look into the carb and open the throttle, does it sqirt fuel ? Do you have a compression tester ? You may have some valves stuck open. You can also pull the covers and check. If stuck get some lube spray and try to spay the valve stems and tap the top of the stem with a hammer with the rocker off. Not to hard. You should get a good bounce. I know this sound like a back yard way of doing things, but I have had to do this when I find an old girl thats been sitting for a bunch of years.