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Yanmar Marine YM Series of Marine Diesels:

Yanmar Marine 3YM marine diesel engine
Specifications: Yanmar Marine 3YM30
Horsepower 29 @ 3600
Displacement 69 Cubic Inches
Bore x Stroke 3.0" x 3.32"
Weight 293 pounds
Cooling Freshwater

Yanmar Marine YM Series of Marine Diesels are More Powerful, Cleaner Burning and in a Compact Package

As the species of Yanmar Marine diesels continues to evolve, we're seeing more power and less weight, at the same time fuel economy improves and exhaust emissions are cleaner. In other words, the new Yanmar Marine's are part of the trend towards smaller, lighter, more powerful and cleaner burning marine diesels.

Case in point is Yanmar Marine's YM series of naturally aspirated four-strokes available in both inboard and sail drive installation packages. The YM30 is a three-cylinder model that's rated 29 horsepower at 3600 rpm. Engineers managed to squeeze 12 percent greater displacement within the same profile as the company's existing three-cylinder engines. So true to this story's preface, here's an engine boasting more power and significantly reduced emissions. This newfound efficiency comes at the hand of a new swirling pre combustion chamber that's fed diesel fuel via indirect (versus direct) fuel injection. There's also a new fuel injection pump that operates at lower rpm for a quieter voice and high efficiency. Obviously the cleaner burn pays big dividends in range and also spells good news for the environment. But onboard it also means less smoke and smell, which might otherwise bother new boaters.

The good news gets even better. The same components that make for more efficient operation also improve cold weather starting. Another big plus is the YM30's electric stop solenoid that quickly and decisively shuts down the engine on command. The house bank of batteries can be charged with either the standard item 60-amp alternator, or the optional (must-have in my book) 80-amp alternator.

Early on in the story we said this engine was particularly compact. Its critical measurements are 26-3/5" long by 17-9/10" wide by 21-1/5" high. Such a diminutive profile means installation on stringers is simple for boat builders on the factory floor or in the shop for a mechanic up to his elbows in a repower.

For the record, the diesel's dry weight comes in at a meagre 293 pounds. Personally, I like the user friendly access for owner operator maintenance chores. The seawater pump, crankcase dipstick and fuel filter are all right out in the open.The compact control panel features an hour- meter for logging engine operation. That makes it easier to schedule fuel and oil filter changes. Complying with EPA Tier 2 regulations, the engine burns cleaner, producing less smoke and lower emission levels.