Fuel Economy
Diesel fuel has a higher energy density than gasoline. On average, 1 gallon of diesel fuel contains approximately 147,000 BTU of potential, while 1 gallon of gasoline contains 125,000 BTU. This, combined with lower operating RPM's and overall efficiency explains why diesel get better fuel economy than equivalent gasoline engine. If 30 percent of passenger vehicles in the United States were powered by diesel engines, the nation would save 350,000 barrels of oil per day.

Fuel Costs
Our fine government has decided to tax gasoline heavily., on average you pay 40-50 cents per gallon that you pump. Since diesel fuels are used in off-road applications some distributors will offer "off-road diesel". These type of fuel is the same as what's offered by any gas station, but its dyed red to indicate its intended use. Over the long term its possible to save a considerable sum of money by going this route. There has been a real surge of commercial lawn care companies moving to diesel and they have been reporting a savings as much as 30-40%.

Longevity
There are a number of reasons why tractor trailer trucks always run diesel engines. Torque for pulling their loads is certianly the first, but in a close second is longevity. Its not uncommon to see highway diesel trucks driving over a million miles before the owner will consider a trade in. The same holds true to diesel tractors. Its safe to assume that a small diesel engine is good for at least 5,000 hours. In car terms that 300,000 miles (@60mph). Consumer gas engines are considered end of life around 1500 hours. Maintenance dictates the true longevity of either model, oil changes are important!

Drawbacks?
Nothing is perfect! Clearly we have presented a solid argument showing that an investment in a diesel can be very worthwhile. Often times, the purchase is exactly that, an investment. Generally speaking a liquid cooled diesel engine can be sold at about $1000 move that their gas counterpart. Large companies like Kubota have easy access though their own manufacturing facilities and can offer a diesel in their own product at a smaller premium. Small companies can purchase gas engines at a competitive price from Kohler for use in their products, economics of scale help keep the cost down. When you examine diesel offerings you find that there can be a considerably larger price gap due to the extra middleman and low sales volumes. Secondly, environmental emissions are higher from diesel than they are from gas. Modern diesels do a much better job than older ones do and its uncommon to notice any foul order. None the less, the impact on the environment is greater.