Have an early 80's merc 7.5 and it seems to start fairly easy and run fair once it is warmed up. I do however have to run it for about 10 min or so before it will run good. It runs for about 7 seconds and then just about dies but then picks right back up and does the same thing again. It seems to do it at idle or half throttle. I took the carb apart to see if it might have been gummed up but everything looks good. I would normally go to start it cold by going full choke pulling and it would almost start, I would then push the choke off and it will fire right up. Should I keep the choke on half for a few mins? thanks