Changes

The engine of choice for a boat is a marine diesel from a manufacturer such as: [http://www.caterpillar.com/ Caterpillar], [http://www.cummins.com/ Cummins], [http://www.detroitdiesel.com/ Detroit Diesel], [cwww.deutz.de/ Deutz], [http://www.northern-lights.com/ Lugger], [http://www.MAN-MEC.com Man], [http://www.Perkins-Sabre.com Perkins], [http://www.Vetus.nl Vetus], [http://www.volvo.com/volvopenta/se/sv-se/ Volvo Penta], [http://www.westerbeke.com/ Westerbeke], [http://www.yanmar.com/ Yanmar], [http://www.ZF-Marine [19.com ZF-30Marine]. Diesels are more efficient per gallon of fuel than a gasoline engine and much much safer. The only significant alternatives on the horizon are fuel cells. [http://boatdiesel.com/ BoatDiesel.Com ] has a wealth of information on diesel engines, transmissions and propellers.

Invented by Rudolf Diesel circa 1898, diesel engines are pressure ignited. They use the familiar four-stroke [https://en.wikipedia.org/wiki/Otto_cycle Otto Cycle ] of intake-compression-combustion-exhaust [31]. <ref>How Engines Work, http://www.keveney.com/Engines.html</ref> Unlike a gasoline engine, which uses spark plugs to ignite a compressed mixture of air and fuel, diesel engines use the heat of compression to ignite the fuel-air mixture. Diesels use very high compression to do this. Like all modern engines, diesels use fuel injectors to spray fuel into the combustion chamber at the precise best moment.

A good diesel engine will produce about 20 hp per gallon/hour compared to 12 hp per gallon/hour for a gasoline engine [34]. <ref>Fuel Horsepower, Tony Athens, http://boatdiesel.com/Articles/</ref> Put another way, a 300-hp diesel will consume about 15 gallons an hour while a similar gasoline engine will consume about 25 gallons.

Diesels are very reliable and robust, but they are only as good as the fuel system. <i>Most troubles with diesel engines stem from the fuel system</i>, and can be prevented through maintenance and a high-quality filtering system. The engine should also be fitted with a starter button, bypassing the one on the bridge; and a dry sump and drip pan.

Religiously maintain filters, injectors and fuel pumps, and inspect fuel lines for leaks. It also helps to use a petroleum solvent such as Pri-D or Run-Right [32<ref>Power Research Inc., http://www.priproducts.com/</ref> <ref>. C.A.T. Products, Inc., http://www.run-33]rite.com/</ref>, but avoid the regular use of [https://en.wikipedia.org/wiki/Biocide biocides], as they are corrosive. Note also that diesel substitutes like bio-diesel, made from vegetable oils, animal fats, and recycled cooking oils, introduce new sets of problems.

[[File:FuelPolishingSystem.jpg|thumb|left|250px|Fuel polishing system for one or two engines with ganged valves. Booster pump flushes air from the system or transfers fuel from tank to tank. Oberdorfer or Walbro pump circulates fuel constantly to polish it. A day tank is not used. Filter details for second engine not shown. Detail of ganged filters not shown.– Adapted from Gulf Coast Filters (http://www.gulfcoastfilters.com/) & SeaSkills (http://www.seaskills.com/)]] A polishing system for two tanks and one engine is shown. It is designed to polish fuel with or without the engine running. When running, the filters can be bypassed if they clog and you need to hot-swop them. If the engine fuel pump fails, the polishing pump serves as a backup to keep the engine going. The vacuum gauge after the filters monitors their condition. A new set of filters will show about 3-inches of mercury. An engine will begin to starve around 10 inches as the filters become restricted [36].<ref>Fuel Filters, Tony Athens, http://boatdiesel.com/Articles/</ref>

 Consider adding a [https://en.wikipedia.org/wiki/Block_heater block heater] to the engine, controlled by a thermostat, to the engine for starting in cold weather. == References == [[Category:PowerpackDiesel]]