The Carter carb may be better than the Roch. but the Roch. is not all that bad. There are many thousands of them still out there running around.
There is no doubt it is running way too rich. It is easy to remove the air horn & check it out. Make sure the power piston is free to go up & down. You need a clear vacuum passage from the intake to the piston. Like has been said previously check the float level. Make sure the float does not have gas in the pontoons. The float drop is not material to this problem but make sure it is correct.
You will need to clean the plugs to get it running.
Turn the idle mixture screw about 2 turns open, start the engine & with a slow idle slowly turn it in till the engine starts slowing down. Then back it out till it speeds back up. That should be the perfect setting.
George
