I have a 75hp mercury 99 model. I used it approx 3 weeks ago. It would not get up on plane. I thought the carbs might be clogged. I put a can of sea foam in the gas, ran the boat over the last couple weeks on the ears not in the lake. Last Friday I went out to crank it up again to make sure it was running before I took it out saturday. It would crank but shut right back off. I decide to take all 3 carbs off and clean them, after cleaning and putting them back on the motor I have the same problem. I then change all my fuel lines, the bulb and check fuel pump I still have the same problem. While changing the lines I took the line off after the fuel pump and started the motor. It will run all the gas out of the carbs but as soon as I put the hose back on it stalls out. Do you think the sea foam made things worse?
Any suggestions will be appreciated.