Re: If it aint one thing . . .
Make sure you are using the proper starting procedure. Trim the motor all the way in. Pump primer bulb until rock hard, give it a few more squeezes. This usually unseats the needles and allows a bit of fuel to trickle through the carbs into the reed blocks, which greatly eases the starting procedure. If the motor is still trimmed out, the fuel just trickles out the venturi and does no good, that is why you trim all the way in. Give 3/4 throttle, crank, and hold choke while cranking. Should start easier. You didn't mention what motor you have, the inline sixes can be a bit balky to start cold.
As has been said, check your lower unit lube. If the leaky substance matches, then you have a leak. If it is dark and smells burned, then it is 2 stroke skank that has worked its way through the exhaust system. Good luck...