Additionally, a ‘glow plug’ supports the spark plug for improved cold-weather starting and better idling.
Mercury’s OptiMax Diesel outboard weighs 234.5kg and delivers 175hp at the propshaft, with an operating range of 5000 to 6000 rpm. It is based on the 3-litre direct fuel-injected OptiMax platform and so behaves more like the 2-stroke gasoline engine it was derived from rather than a typical 4-stroke diesel engine.
The military-issue diesel outboard currently does not meet US exhaust emissions regulations so it cannot be released as a consumer engine. However, Mercury said that if it can find a way to meet the emissions standards in the future then these units may be released as consumer outboards as well.