4 Hp Evinrude For Sale I Have A 1980 Johnson Evinrude 115 HP 4 Cyl, Dual Carb That Runs Well In The Driveway With "earmuffs"

I have a 1980 Johnson Evinrude 115 HP 4 cyl, dual carb that runs well in the driveway with "earmuffs" - 4 hp evinrude for sale

However, if the water starts and warm, hiking, even for a while, but under tension (front and back), it is a slow burning gas like crazy. Someone knows what could that be? When is a carbohydrate, how can I know what you?

Thank you for any help!