I have a 1992 Merc 5.0 LX that is hard to start when warm. Sometimes impossible. I removed the flame arrestor and noiced the butterfly choke was closing when I tried to start the engine. If I manually held the choke open it would start. I am guessing that my choke spring is getting lazy after 17 years. I believe the carb is a Rochester 4MV. (or C but I don't know the difference and the shop manual doesn't specify the difference) I believe the Merc part number is 1347-9661. I do not see a method to adjust the choke spring tension. According to the shop manual the only choke setting I see is to bend the choke spring arm so the holes line up. Can I bend the choke spring arm more to adjust or how do I adjust? Or do I need to just buy a new choke spring?
