1975 25 horse engine back fires through exhaust

[rpmdj1]

1975 25 horse evinrude

ok I turn it over with new starter and it turns fine but backfires through the exhaust I got spark compression fuel so what gives
I'm about done with this motor

 

[racerone]

These are very good motors.--------If the plug wires are reversed the motor will bark at you like a wild dog.-----Check that.

 

[Faztbullet]

Pop out the exhaust is usually ignition related and out carb is fuel related