5hp Merc wont stay running. Gas?

I have a 5hp serial number OD983433 and it has hardly been used.. Grease still on cables. Having issues keeping it running. I can get it to start and idle for a few but then it dies on me. I also noticed that when I turn the gas on and it flows into the filter to carb it dies right then and there. Im using the attached tank on the back of motor. I've tried regular gas, 93 gas mixed different ways. It's a little smokey but I guess thats normal. Not sure what the deal is here. I took carb off and cleaned it out real good. put it back on and it fired up first pull, ran a few seconds and then died on me. Any ideas and also what is the best gas to use on this motor?

kimcrwbr1 said:

87 octane with TCW3 oil mixed to 50:1. Sounds like your float needle and seat is bad flooding the motor or the float is full of fuel?

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I was thinking float. Gonna mess with that and change out my gas.