1980 50hp Merc Idles rough but smooths out under power.

[Tommy Good]

Hi: This is my first post so if this has been gone over before please excuse me. My 1980 50hp Merc idles rough but will smooth out and run well when the motor is in gear and throttled up and under a load. It continues to run well until I bring it back down toward idle and then it begins to run rough again. When out of the water and using those water injecting ear muffs. It will idle rough and continue to run rough when the transmission is ingaged and the motor is throttled up. It only runs smooth when in the lake and the transmission is engaged and the motor is throttled up. It pushes my 16ft aluminum bass boat 30-35 mph. I will take my GPS out the next time to get a more accurate speed. Can anyone help me?

 

[randycc58]

Re: 1980 50hp Merc Idles rough but smooths out under power.

I believe you are going to asked a lot of questions. If you dont have the book on your motor, you should get one. Available here. 2nd. has the boat sat up for a long time? Dirty carbs?Good plugs? compression? in short, how many of the basics have you done? But good news. You came to the right place for help. The guys here are great at helping, and should get you headed in the right direction.