First, some discussion on the viability of diesel outboard motors. Outboard motors have progressed from lightweight, simple to manufacture 2-stroke engines to more complicated, but less polluting, 4-stroke gas models. Would diesel power be the next logical step?
Other Marine Diesel Engine Manufacturers HERE
Positive aspect of diesel power for outboard motors:
High torque: Diesel engines produce significantly more torque than gas engines for similar horsepower and displacement. Torque equals acceleration and the ability to produce sufficient power at lower RPMs.
Fuel efficiency: Marine Diesel engines get more miles per gallon. In inboard applications, marine diesel engines can provide up to twice the range of marine gas engines for the same amount of fuel used.
Lower maintenance: Gas engines need regular tuneups with spark plug changes and timing adjustments. Maintenance for diesel engines generally just involve oil and filter changes, often at greater intervals than their gas counterparts.
Longevity: Diesel engines are of sturdier manufacture to withstand the high compression ratios of compression ignition. This results in engines that typically can outlast 3 or 4 of comparable gas motors.
Negative aspects of diesel power for outboard motor applications:
Weight: The same thing that makes diesels durable and long lasting is is a detriment to outboard motor power applications. Diesels typically weigh significantly more than gas engines with the same output.
Pollution: Diesels require serious technology to turn their typically smokey exhaust into EPA friendly emissions. This adds weight and cost. Diesel noise could also be considered a type of pollution.
Cost: Diesels are significantly more expensive than gas engines. Manufacturers would have to prove other savings over the current gas outboard motor engines.
Consider Carbon Offsets to balance environmental impact of burning fuel HERE
There have been some diesel outboard motors available at various times. Many were low horsepower models produced in Asia and not sent to the U.S. The most prevalent were diesel outboard engines produced by Yanmar. The Yanmar D27 and D36 produced 27 and 36 hp. respectively. Although no longer in production, the Internet is full of parties worldwide looking to buy used outboard motors. The Yanmar D36 sold for about $8,000 in 1998. Note: the photo to the right is a D36.
I also found the website of the Maritime Engineering Group of Fort Myers, FL. The company is testing 2.3L and 3.0L Diesel outboard engines that appear to be powerful, fuel efficient and of reasonable weight. The news and press releases from the site are dated 2007 so the continued existence of the possibility of a modern diesel outboard motor is in question.
Find a Marina to Service Your Yamaha Diesel Outboard Motor HERE.
Outboard Motor Sources: Yanmar, Maritime Engineering Group
- Yamaha Outboard Engine Facts
- Outboard Motors with Self Contained Gas Tanks
- Marine Engine Manufacturers – Outboard
- Evinrude Outboard Engine Facts
- Champion Outboard Engine History