freddyray21
Commander
- Joined
- Jun 10, 2006
- Messages
- 2,460
1972 Mercruiser 120 hp serial number on engine 2770087. Took the carb off today to rebuild it due to it loading up at an idle. (new problem just developed after putting new oem fuel pump on it. Old fuel pump went out when brother ran boat out of gas. I think it was weak and ready to go and running it dry did it in). After replacing the fuel pump my daughter and I went out for a 30 mile run in it and had no problems until we came into the ramp. It loaded up and died. I thought carb adjustment so got it home put it on the muffs and adjusted the carb where it smoothed out nicely and idled well. Went out today with friends. It started fine and we went downriver to a hole to play in. Shut it off to let a tuber in the water and would not start right up. Had to push the throttle only button in and advanced the throttle for a flooded motor and it started. Let it run the gas out and brought it back to an idle and pulled my tuber, but after that every time we needed to idle down it would flood out. So I took the carb off and pulled it apart. There is some grit in it that I think was sucked in when my brother ran the tank dry. Don't see how it got past the fuel water separator, an inline filter and the built in filter in the pump, but it did. In any event was looking at my manual to read the procedure and my manual states a 120 does not have a power piston, but the carb I pulled off does. I first thought someone put a auto carb on it, but the carb number stamped on the body checks to be a Rochester marine carb. Is is possible someone put a 140 carb on it and will it make a difference. This is my third season with this boat and it's always ran well with this carb until now.
