Hello everyone, I'm new to this site and really need some help with my boat. I have a 1976 Johnson 55 hp Seahorse. It will run all day long on land with the muffs and water of course, but when you put it in the lake, it will only start for about a minute, then die and will not start again. I'm lost for causes. Its got a new ignition switch, carbs rebuilt, new starter, new plugs gapped at .040, new power pack, new batteries. The choke silonoid readjusted to 3/16" and floats adjusted to 1/16". Fuel filiter cleaned, with new fuel with a mixture of 20 ounces per 6 gallons. Any help will be greatly appreciated. I've never seen a boat that will run on land and not in the water!! Now this is hilarious!