Hello fellow boatsmen<br /><br />Johnson 50 '84, Mod. nr. J50BELCRM<br /><br />In coldstart engine starts easily, but it stops shortly after, requiring several attempts with choke on/off 5-7 times before it is able to keep running. Operating in the water, there is a threshold to how much throttle the engine can take before it dies i.e. it will not reach high rpm in normal operating conditions. Becauase of this we are not able to get the boat up "in plane", it acts kinda jerky in this threshold, managed one time to _almost_ get it fully in plane, but it just suddenly dropped when almost in full plane. In a test tank I can get the engine up to high rpm's, obviously because there is no load. During test in a water tank I find it somewhat stumbeling and not smooth running, sometimes I can hear it running kind of ok, and suddenly hear a serious drop in rpm, almost like it misfires. If I remove the spark plug lead from the top cylinder it keeps running, if I remove the bottom spark plug lead the engine stops or at least have more difficulty running.<br /><br />I have serviced the carburators according to the manual, cleaned for dirt and debris, changed inlet valves, and synchronized them. After carb service it starts more easily than before, however as said it will not keep running, this takes about 5-7 attempts. Probably unrelated, but compression is good.<br /><br />Thanks for any input, hope I did a better job presenting the problem this time.. 