Miss fire

[Lab5221]

My 2006 140 suzuki outboard when started idles rough and black smoke and also has a miss fire in the engine,had a3 2 code changed the map sensor same problem

[redlowrey]

My 2006 140 suzuki outboard when started idles rough and black smoke and also has a miss fire in the engine,had a3 2 code changed the map sensor same problem

As I have said many times on this forum don't change the map sensor till you have done some basic tests. When an engine is running good high manifold vacuum will be produced in the inlet manifold, the ECU uses a map sensor to read this and converts it into a voltage, at idle around one to one and a half volts and wide open throttle a bit over four volts. Any mechanical or electrical problem that affects the running of the engine will change manifold vacuum, ie, signal line voltage to the ecu. First pull the plugs out and see if there all black or one is wet and do a compression test.