[NeighborsComplaint]

Blow-by smells like oil.

A rich mixture will smell like gas, the emissions are unburnt hydrocarbons. Starting may require holding your foot to the floor while cranking to get enough air to fire.

A lean mixture send excessive amounts of NOx out the exhaust. It smells like insecticide and burns the eyes.

Pull a sparkplug under idle and at cruise (shift to neutral, cut the ignition and coast to a spot where you can pull a plug without idling the engine again.

Rich = black and sooty deposits, Normal = brown to tan tip, Lean = Very light tan to white/gray tip.