I just bought a 1983 H34 with a Yanmar 20 hp. Does anyone know if there is a fuel guage and it's location. I couldn't find one. If not, can someone give me a range of how much fuel I should expect to burn so that I can somehow estimate fuel consumption. Thanks.
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Estimate.
Joe: You can estimate .75 - 1.0 gal/hr., if you run your engine at the recommended cruising rpm of 70-80% of max 2500-2900rpm. If you run at lower RPM's, it may be slightly less. You can also purchase a fuel gauge from the web site. They stick on the outside of the fuel tank.
Joe: You can estimate .75 - 1.0 gal/hr., if you run your engine at the recommended cruising rpm of 70-80% of max 2500-2900rpm. If you run at lower RPM's, it may be slightly less. You can also purchase a fuel gauge from the web site. They stick on the outside of the fuel tank.
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Michael
Fuel Gauge and Yanmar 20 HP performance
Joe, Here is the spec for Yanmar 2QM20 20 hp installed on my 1981 Hunter 36: approx. 2.5 l/hr @ 1200 RPM or 3.5 l/hr @ 2000 RPM (an average of cruising speed of 4.5 knots) and 4.5 l/hr @ 2400 RPM. My fuel tank capacity is 30 US gallons (115 l) so at nominal 2000 rpm you may roll for 40 hours. Regarding the fuel gauge location: mine is installed close coupled on top of the tank and may be seen through the rotating cover on cockpit port side (use a flush light).
Joe, Here is the spec for Yanmar 2QM20 20 hp installed on my 1981 Hunter 36: approx. 2.5 l/hr @ 1200 RPM or 3.5 l/hr @ 2000 RPM (an average of cruising speed of 4.5 knots) and 4.5 l/hr @ 2400 RPM. My fuel tank capacity is 30 US gallons (115 l) so at nominal 2000 rpm you may roll for 40 hours. Regarding the fuel gauge location: mine is installed close coupled on top of the tank and may be seen through the rotating cover on cockpit port side (use a flush light).
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Tim Schaaf
So much fuel as that?
I am amazed that everyone is using so much fuel. As a general rule, almost any diesel in good condition will burn .05 gallon per hour per horsepower. Thus, a twenty HP engine should burn about a gallon per hour at maximum output. For example, cruising at about 5.2 to 5.5 knots in my Hunter 33 (displacing a bit over 12,000 lbs, with tanks partly full and with gear aboard, but no crew), I use from .4 to .5 gallons per hour. I know that the 34 is a much bigger boat, but the waterline is also longer, so the equivalent speed represents a lower speed/ length ratio. Since I am using only 8 to 10 of the 14 continuous available horsepower, I am surprised that the 34 uses so much. With a clean bottom, a correctly sized prop, a well maintained engine, and flat water and no wind, you should be able to get the engine right the way up to its rated speed, or very, very close. If you are not able to do this, the prop is too big for the way the boat is loaded, and something is slowing the boat down. Often, if the boat is not equipped with an engine with much margin of power, simply adding a lot of stuff weighs the boat down enough to increase the wetted surface (hence drag) sufficiently to get this result. Better get rid of some of the weight, or, if not, get a smaller prop. It will be better on your engine. Then again, if the bottom is dirty..........! But, if a 20 horsepower engine is consuming a gallon per hour, (its theoretical max) and is not getting anywhere near its rated RPM'S, nor is moving the boat at a speed at least equivalent to the square root of its waterline length, I would start poking around. I don't mean to get anyone stirred up, but......
I am amazed that everyone is using so much fuel. As a general rule, almost any diesel in good condition will burn .05 gallon per hour per horsepower. Thus, a twenty HP engine should burn about a gallon per hour at maximum output. For example, cruising at about 5.2 to 5.5 knots in my Hunter 33 (displacing a bit over 12,000 lbs, with tanks partly full and with gear aboard, but no crew), I use from .4 to .5 gallons per hour. I know that the 34 is a much bigger boat, but the waterline is also longer, so the equivalent speed represents a lower speed/ length ratio. Since I am using only 8 to 10 of the 14 continuous available horsepower, I am surprised that the 34 uses so much. With a clean bottom, a correctly sized prop, a well maintained engine, and flat water and no wind, you should be able to get the engine right the way up to its rated speed, or very, very close. If you are not able to do this, the prop is too big for the way the boat is loaded, and something is slowing the boat down. Often, if the boat is not equipped with an engine with much margin of power, simply adding a lot of stuff weighs the boat down enough to increase the wetted surface (hence drag) sufficiently to get this result. Better get rid of some of the weight, or, if not, get a smaller prop. It will be better on your engine. Then again, if the bottom is dirty..........! But, if a 20 horsepower engine is consuming a gallon per hour, (its theoretical max) and is not getting anywhere near its rated RPM'S, nor is moving the boat at a speed at least equivalent to the square root of its waterline length, I would start poking around. I don't mean to get anyone stirred up, but......
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Don
Stud finder
Search the archives. There are numerous suggestions for checking the fuel level in the 34/31 models. I used a stud finder on the tank, worked great.
Search the archives. There are numerous suggestions for checking the fuel level in the 34/31 models. I used a stud finder on the tank, worked great.
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Bruce
I installed a mechanical gauge
There have been discussions here about fuel gauges and estimating. I installed a mechanical gauge (available through West Marine) in my tank and wish I had done it earlier. I cannot imagine why it is not standard. You might check the archives, but if you are interested in what I did and what was involved, let me know. I agree with Tim about fuel consumption. My H34 with its 3GMF Yanmar seems to average about 1/2 gal per hour at cruise. Bruce bchase3@aol.com Annapolis
There have been discussions here about fuel gauges and estimating. I installed a mechanical gauge (available through West Marine) in my tank and wish I had done it earlier. I cannot imagine why it is not standard. You might check the archives, but if you are interested in what I did and what was involved, let me know. I agree with Tim about fuel consumption. My H34 with its 3GMF Yanmar seems to average about 1/2 gal per hour at cruise. Bruce bchase3@aol.com Annapolis
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Steve O.
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Dick Carey
Fuel Burn Rate for 2GM20F
I have a 2GM20F (18-20HP) and have kept careful fuel & engine hour records for the past two seasons. Before I changed the mixing elbow to a new one the fuel rate (average over the season) was 0.40 GPH. After the new mixing elbow the following season rate was 0.28 GPH (season average). The tank is white semi-translucent polyethelyne with a fuel gage on top which is a rough indicator. I also made permanent marker marks on the side with calculated Gal. level marks. I just raise the rear most hatch cover, over the tank, to let sunlight in and view the tank side thru the main storgae locker under the starboard cockpit seat. This gives me a close 'Gal. remaining' number to go by and to determine when it's time to add more diesel fuel. On a cloudy day a flahlight placed on the top of the tank near the side with the marks works fine also. Dick Carey S/V Puffin
I have a 2GM20F (18-20HP) and have kept careful fuel & engine hour records for the past two seasons. Before I changed the mixing elbow to a new one the fuel rate (average over the season) was 0.40 GPH. After the new mixing elbow the following season rate was 0.28 GPH (season average). The tank is white semi-translucent polyethelyne with a fuel gage on top which is a rough indicator. I also made permanent marker marks on the side with calculated Gal. level marks. I just raise the rear most hatch cover, over the tank, to let sunlight in and view the tank side thru the main storgae locker under the starboard cockpit seat. This gives me a close 'Gal. remaining' number to go by and to determine when it's time to add more diesel fuel. On a cloudy day a flahlight placed on the top of the tank near the side with the marks works fine also. Dick Carey S/V Puffin
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Rich Wallace
Fuel Burn On A 3GMF
The diesel engine in your boat if it is original is a 3GMF. 3 Cylinder, 20 HP. Running around 2900 RPM you will burn around 3/4 of a gallon an hour. If you have the original 15x12 prop that will be around 5.7 knots. (The boat should have had a 15x15 prop. There are some postings in the archives about a modification that Kilian Propeller in California can do to your present prop that will get you almost a whole knot at 2900 RPM. The mod is $130 to $140 vs. $300+ for a new prop. They are closed for a move now but should be back on-line by fall.) I put a sending unit in the tank and mounted a fuel gauge just to the left of the engine panel in the cockpit. It does give a lot of piece of mind to have the gauge in plain sight all the time.
The diesel engine in your boat if it is original is a 3GMF. 3 Cylinder, 20 HP. Running around 2900 RPM you will burn around 3/4 of a gallon an hour. If you have the original 15x12 prop that will be around 5.7 knots. (The boat should have had a 15x15 prop. There are some postings in the archives about a modification that Kilian Propeller in California can do to your present prop that will get you almost a whole knot at 2900 RPM. The mod is $130 to $140 vs. $300+ for a new prop. They are closed for a move now but should be back on-line by fall.) I put a sending unit in the tank and mounted a fuel gauge just to the left of the engine panel in the cockpit. It does give a lot of piece of mind to have the gauge in plain sight all the time.
K
Ken Hunter
H34 Yanmar Fuel Consumption
My H34 w/3GMF uses about .5 to .75 gal per hour depending on all the load, wind & current factors. I usually top the tank off after about 20 to 25 hours of run time. I always carry a 5 gal spare. Ken Hunter H34 Sea Myst
My H34 w/3GMF uses about .5 to .75 gal per hour depending on all the load, wind & current factors. I usually top the tank off after about 20 to 25 hours of run time. I always carry a 5 gal spare. Ken Hunter H34 Sea Myst
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