Hi, trying to help my dad. He is a retired vet and just bought his first boat (used). Its not as good as they said. It runs great on land with with muffs. When we take it out it won't idle. We can force in to gear and it runs fine no matter where the throtle is set. We checked compression its good. Changed the pulgs. cleaned the carbs. and replaced the valve seats and the floats. We also pulled the lower unit and looked at water pump looks like new. Was woundering if anyone might no of something else we can do. Thanks for any advice!