This is something I have never experienced before. My 91 70hp johnson is on a 20' party barge. When I have a load of people more than me and my wife and child the motor will start to bog down, I can push the chole in and it will pick back up, if I pump the choke it keeps it at full speed, I worried I might damage something doing this, If I kick everybody off the boat it starts running fine. I can not figure out what the problem is, Gas, Carbs or bad plugs??? I dont know, none look fouled, the gas is new, hope yall can help me with this one.
