#Yanmar 8 hp diesel fuel how to#

You want your engine to run at the optimal RPM.Д¬hoose the right prop size - The right propellor is crucial to get an efficiently-running motor. Don't overpower and don't underpower your boat. Lowering weight means a lot more range on that tank. If you carry ballast, now is the time to unload it. Just as you would while sailing (but don't go overboard with this either). Take the wind direction and current into account. It really improves mileage a lot if you take it down a knot.ДЇind the right course. Engines are most efficient between 75-85% of their maximum RPM. This will cause the engine to rev up to maximum RPM.

#Yanmar 8 hp diesel fuel how to#

So how to make it happen?Дon't drive at hull speed. If you need to save your fuel, but you need to get out, for example in an emergency, you want to make sure you get as far as possible as fast as possible. Very strong (ocean) currents can also double the burn rate. If you have to head into a strong current, that's not good as well. Water conditions - As mentioned, high waves are not good for fuel consumption. Strong winds create high waves which will cause your fuel economy to sink. Wind direction - Driving straight into a headwind could almost double fuel consumption. Flat bottom boats use even less (but are less appropriate for sailing). You'll see when you drive a catamaran: it uses WAY less fuel. Also, multihulls displace a lot less water, making them way more efficient. The bulkier the shape, the more water it has to push away, so the more fuel it uses. Hull type and shape - The shape of the hull determines how much water it displaces. If you want to read more on how to choose the right engine size, I've written this short guide on calculating the right size. The right size propellor is also important. 2-stroke engines are more powerful but also use a lot more fuel for example. There are some other engine factors, like type the number of cylinders. Most sailboats are fine with a 30HP engine in most circumstances. But if you're on the open sea and have a large boat (let's say 40' and up), you want something stronger to deal with the current and wind. Most of the times people have too big of an engine, and sailboats don't require very large engines.

The engine has to work too hard making it rev up (it runs on maximum RPM), burning more fuel. But if you're engine is too small, it could potentially use more fuel. Some of them are:Д®ngine size and power - Larger engines use more fuel. There are a lot of factors that determine how much your engine actually burn. Here are my estimates for bad conditions: Engine powerДЄs you can see, fuel use widely varies.

Here are the manufacturers estimates: Engine power The number is in liters, you have to convert it to gallons. So if you want to calculate your engine's fuel consumption, simply multiply 170 or 250 with the amount of HP. So I've also added a more conservative estimate, based on 250 grams per hour per horsepower.I want to remind you that these are the manufacturer's numbers, so they're probably optimistic. Yanmar uses an average fuel consumption of 170 grams per hour per horsepower.I've found the average fuel consumption in the Yanmar manual. I want to know a range for each engine size. Larger 50HP engines may use up to 2.5 GPH if the conditions are bad and you max it out at, let's say, 8 knots.

large sailboats use on average 1.8 - 3.3 GPH.

mid-sized sailboats use on average 0.9 - 2 GPH.

small sailboats use on average 0.5 - 1 GPH.

So let's take a look at what different sizes use on average: Of course, the size of the boat (and engine) and fuel consumption are related. So the range on one hour of motoring can be anywhere from 4 - 8 nautical miles. Most sailboats cruise at a speed of 4 - 8 knots under engine. The distance you cover isn't fixed at all. We measure fuel consumption in Gallons Per Hour (GPH), because the time the engine is running is the only fixed variable here.