Car wouldn't start, thought it wa flooded, disconnected air cleaner, but after trying to start fuel started flooding into air cleaner tray. Opened choke and sprayed carby cleaner; tried again, got a puff of carby cleaner mist then engine started - smoke from exhaust was very thick and wouldn't stop. Turned it off; started it again later - idled good then fuel started flooding back into air cleaner tray. Meanwhile - low reading on oil dip stick prompted me to put more in. I had put some oil in a few days previous so thought low reading was strange. I decided to drain some oil out of sump and found a mixture of fuel and oil - lots of petrol. Is the carby causing problems or have I also got stuffed rings?