Hirth F-23, Operator'S Manual

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9
GASOLINE AND OIL
Contaminated fuel is a major cause of engine failure. Before you introduce fuel into the fuel
system, be sure to take precautions to see if your fuel is contaminated. Check for water, dirt,
crud and other undesirable substances.
GASOLINE
Use Premium unleaded auto gas. If possible avoid using gas that has ethanol or methanol
mixed with it. Aviation 100 LL can be used occasionally but will decrease spark plug and
piston ring life substantially. The lead in 100LL sticks to engine parts the same as carbon
deposits.
OIL
50:1 Ratio oils: Use a high quality name brand two cycle engine oil for air cooled engines with
corrosion inhibitor, preferably with a low ash content. If fuel injected mix at 45:1
100:1 Ratio oils: Blue Max is the only 100:1 oil that has been tested and approved by Hirth. If
you elect to use Blue Max it should be mixed at 90:l. Do not use Blue Max at ratios lower than
90:1. There will be too many lubricants introduced into the system and they may not all burn
off. In which case, piston rings may stick in only a few hours. Do not use Blue Max pre mix oil
in engines equipped with oil injection. For oil injected engines use Blue Max injection oil.
NOTE: If engine is fuel injected, mix Blue Max at 90:1
–
1.42oz of oil per gallon of gas.
FUEL MIXTURE
In this manual, gasoline and oil mixed together are referred to as fuel.
Gasoline/oil mix ration of 2%. (50:1) | Gasoline/oil mix ration of 1%. (100:1)
1 unit of oil to 50 units of gasoline. | 1 unit of oil to 100 units of gasoline.
200 ml of oil to 10 liters of gasoline. | 100 ml of oil to 10 liters of gasoline.
12.8 fl oz of oil to 5 gallons of gasoline | 6.4 fl oz of oil to 5 gallons of gasoline
Oil Mixing formula 50:1: 2.56, X gallons being mixed. Example-5 gallons at 50:1 - 2.56, X 5
gallons = 12.8 oz. of oil. / 6 gallons at 50:1
–
2.56 X 6 gallons = 15.36 oz.
Oil Mixing formula 100:1: 1.28, X gallons being mixed. Example-5 gallons at 100:1- 1.28, X
5 gallons = 6.4 oz. of oil. / 6 gallons at 100:1
–
1.28 X 6 gallons = 7.68 oz.
MIXING PROCEDURE:
1.
Always premix oil and gasoline.
2. Use an approved container of known volume.
3. Ensure container is clean.
4. Add 1 gallon of gasoline.
5. Add pre measured (By above formulas) 2 cycle oil.
6. Shake container vigorously.
7. Add remaining gasoline required to fill container.
8. Shake container again lightly to complete the fuel mix.
Ground aircraft or vehicle to fuel dispenser with a grounding wire when required. Filter fuel
through a fine mesh screen before it enters the tank.
If equipped with optional oil injection refer to oil injection manual for lubrication
information.
#1 CHECK. (TO BE PERFORMED BEFORE EVERY FLIGHT)