I am working on my 1958 Merc mark 10 I picked up a few years ago. It has 115 and 115 compression, new Sierra condensers, have changed the coils for the THIRD time, they read 7.3 ohms…both of them and tested for continuity wire to wire, there not new but no change with these ones…. from a running engine. I have cleaned the original carb TWICE. I tried two other carbs as well and set them over and over…one turn out, one and a half….two…no difference. If you spin it with the plugs out and grounded on the engine there is excellent spark. I just finished putting a water pump impeller in it and it is pumping great water now…not the easiest impeller I have ever changed but its in and working great….and it will hardly run….spits and sputters and quits over and over again. It will rev up a little and sputter and die. I tried another flywheel, cleaned and set the points OVER AND OVER, took them OUT and cleaned with 600 grit…plain paper drawn through them to clean….Changed the fuel pump, I knew that was not it, it should run until the carb is empty. I have worked on a lot of old motors but never seen anything like this. Anyone got any ideas?? Got good gas, good spark and great compression for one of these and can’t even get it to idle. ANY idea’s would be welcome!