1. Dirty or clogged air filter element.
2. Incorrectly set ignition timing.
3. Choke sticking or improperly adjusted. Carb models.
4. Emissions system not functioning properly.
5. Carb/Fuel injection internal parts excessivley worn or damaged.
6. Low tire pressure or incorrect tire size.

2. Fuel leakage and/or fuel odor

1. Leak in a fuel line.
2. Tank overfilled. Fill only to automatic shut off.
3. Emissions system filter clogged.
4. Vapour leaks from system lines.
5. Carburator/Fuel injection internal parts excessively worn.