1992 20hp merc air leak

any help would be appreciated. so i think i have an air leak somewhere between the fuel to motor connector and the fuel filter.i can start the motor and run it no problem but when i put it in the water and open it up a bit it quickly dies. i take the cowling off and notice there is no fuel in the fuel line from the filter to the carb. i have clear fuel lines so that part is simple. ill sit for a few mins fuel will make its way around the air bubble. prime it a few times and its back in buisness for a few mins. I've checked the filter and everything is good with that. so i bought a new fuel line, tank,and connectors for both ends. it worked for a few outings then same problem. now I've been running it with the cowling off and can see the air moving up the line from the motor connection. it seems like its creating an air bubble between the carb and the rest of the fuel. I've bought another FTM connection since and it fixed the problem for about a week and now its back. one thing to note is as i flush my motor ill pull the fuel line off to burn up what fuel i can in the motor. is the FTM connector going bad because I'm taking it on and off? this seems to be the only thing that makes since