Gas vs. Diesel

BCS 853 with Kohler diesel & 5x12x22” wheels

One of the questions we get asked all the time is: “What is the best engine for me? Gas or Diesel?” Well, here are some reasons to mull over:

First, we’ll do diesel PROS:

  1. Properly maintained, a diesel engine can last 2 to 3 times as long as a gasoline engine. (This is why the diesels cost more … you are buying the “potential lifespan” up front.)
  2. In these small air-cooled engines, diesels use ½ to 1/3 the amount of fuel a gas engine consumes doing the same work. (This is where diesels can “pay off” … IF you’re using the tractor enough hours per year.)
  3. Diesel engines give the option of running lower-cost and/or environmentally friendlier BioDiesel fuel.
  4. Better low-speed torque on a diesel engine (Note that the diesel engine options on most of the tractors have a lower horsepower rating than the gas option … but from a working standpoint, the “working torque” averages close to the same as the gas. [The diesel has more torque at low engine speeds, but the gas has more torque at full engine speed.])

And, to be fair, here are some ‘CONS’ to the diesel engines:

  1. More noise than a gas engine
  2. More vibration than a gas engine
  3. More initial cost than a gas engine
  4. Harder starting in cold weather
  5. Virtually requires the electric start option, while the gas engines start easily with manual start
  6. Heavier than Gas engines (may require extra implement counter-balancing)
  7. Typically harder to find local parts & service for the diesel engines (service centers for the gas engine options are very common)
  8. Diesels are fussier about moisture in the fuel…in a Gas engine, water in the fuel will cause the engine to run poorly; when you get the water out, the engine will typically be OK. If you get water in a diesel fuel system, however, you will quickly spend several hundred dollars for a new fuel injection system, because a few drops of water can RUIN it!

Most of the time, the choice comes down to Economics: how long will it take for the cost savings of running a diesel to pay for the higher initial investment? Typically, folks who are putting a lot of hours on the tractor (200 to 250 plus hours per year) would be well advised to consider the diesel, because the extra investment will pay off in a reasonable amount of time. Of course, the higher the price of fuel is, the quicker it pays off! (even if diesel fuel is more expensive than gasoline, the fuel cost savings still add up–more slowly, of course–but keep in mind that the diesel uses ½ to 1/3 the fuel of the gas engines.)

If the tractor is only used 50 - 100 hours or so per year, diesel is really not an economically desirable option…it would take a lifetime (or more) to pay for itself. (Unless, of course, you would choose the diesel solely based on other reasons, like being able to use a biofuel, etc.)

We have the most experience with the Italian made Lombardini (now owned by the American company Kohler) diesel engines which have been standard equipment in Europe on BCS and Grillo machines for over 25 years. We stock parts, for and provide authorized warranty service for, the Lombardini/Kohler diesels. We keep filters and a few other parts in stock for the Yanmar diesel engines (which were used on a few BCS machines), but we are NOT an authorized warranty or repair center for Yanmar.