Ok i have a 1980 70hp 3 cyl Merc that is rough running with no ability to idle and back fires some at higher RPM's. I've started with new plugs, new gas, rebuild carbs now whats next... The video should support the rough running engine followed by some back firing...
Engine doesn't idle very well and continues to spurter but NO back fire.
It has new fuel 50:1
New plugs
What else can a person do to rectify this situ?