Fuel Testing 2/8/2003

Everyone has an opinion about what fuel is best and trying a new fuel is often done when a new engine will not start. I chose Methanol (wood alcohol) for my first engine and have continued to use it. My logic was based on having an air conditioned shop with limited ventilation, so a clean fuel is needed.

I tested various fuels and mixes using the same horizontal hit and miss engine and carburetor. Each test began with a cold engine and ended with a run that was over two hours. The new fuel was changed at the end of the previous test to get an initial carburetor setting. Since Methanol was my preferred fuel I use it as a base for comparisons.

Methanol

Carburetor Setting: 6/12 turn

Temperature Rise: 43F

Cold Starting: First start is very hard, after a minute of running the second flip is good.

Warm Stating: First flip

Notes: Virtually no odor. Fuel has no lubricating properties, after 15 minutes of run engine stops due to dry cylinder. It was found 1 drop of #20 non-detergent oil added every 10 minutes kept it running well and there were signs of oil on the valves and in the cylinder. See notes about oiling the cylinder.

 

Coleman Stove Fuel

Carburetor Setting: 11/12 turn

Temperature Rise: 33F

Cold Starting: Needed extra fuel to start cold. Was easier to start.

Warm Stating: First flip but accelerates to operating speed more slowly

Notes: Low burnt solvent odor. Fuel has no lubricating properties 1 drop of #20 non-detergent oil, added every 10 minutes kept it running well and there were signs of oil on the valves and in the cylinder. There was a small amount of black carbon in the oil in side the cylinder.

 

25% Coleman Stove Fuel + 75%Methanol

Carburetor Setting: 6/12 turn

Temperature Rise: 36F

Cold Starting: First start took 5 flips, after that if was first flip.

Warm Stating: First flip, accelerates more rapidly, exhaust louder.

Notes: Low burnt solvent odor. Fuel has no lubricating properties 1 drop of #20 non-detergent oil, added every 10 minutes kept it running well and there were signs of oil on the valves and in the cylinder. The black carbon was not visible. Better operation than either fuel alone.

 

90% Regular Gasoline + 10% WD-40

Carburetor Setting: 12/12 turn

Temperature Rise: 34F

Cold Starting: Started on second flip.

Warm Stating: First flip every time

Notes: Exhaust odor was strong and built with time. Fuel has lubricating so no extra oil was used. Exhaust was very visible, may have been smoke or oil mist. Under the exhaust port a small puddle of black oily material accumulated. There were signs of oil on the valves and in the cylinder. There was a small amount of black carbon in the oil in side the cylinder. This regular gas mix kept the cylinder cleanest.

 

95% Regular Gasoline + 5% WD-40

Carburetor Setting: 12/12 turn

Temperature Rise: 32F

Cold Starting: Started on second flip.

Warm Stating: First flip every time, aggressive starting speed.

Notes: Exhaust odor was strong and built with time. Fuel has lubricating so no extra oil was used. Exhaust was just visible, may have been smoke or oil mist. Under the exhaust port a few drops of black oily material accumulated. There were signs of oil on the valves and in the cylinder. There was a more black carbon in the oil in side the cylinder than with the 10% mix, making the parts black in 2.5 hours. This was the easiest starting regular gas mix.

 

Regular Gasoline

Carburetor Setting: 12/12 turn

Temperature Rise:

Cold Starting: Started on second flip.

Warm Stating: First flip every time, aggressive starting speed.

Notes: Exhaust odor was strong. Fuel has no lubricating properties 1 drop of #20 non-detergent oil added every 10 minutes kept it running well. The engine stopped operating after 35 minutes due to carbon fouling of the spark plug. The plug, valves head and piston top were covered with a layer of fluffy black carbon dust. There were no signs of oil on the valves and in the cylinder. The fuel was abandoned.

 

24% Coleman Stove Fuel + 74%Methanol + 2% WD-40

Carburetor Setting: 11/12 turn

Temperature Rise: 40F

Cold Starting: First start took 7 flips, after that if was first or second flip.

Warm Stating: First flip, accelerates well.

Notes: Low burnt solvent and oil odor. Fuel has low lubricating properties 1 drop of #20 non-detergent oil, added every 10 minutes kept it running well and there were signs of oil on the valves and in the cylinder. Exhaust made a stain but was probably one drop of oil with carbon... The WD-40 added little.

 

Propane (demand regulator)

Carburetor Setting: 48/12 turn

Temperature Rise: 42F

Cold Starting: First flip every time.

Warm Stating: First flip every time, aggressive.

Notes: Virtually no odor. Fuel has low lubricating properties 1 drop of #20 non-detergent oil, added every 10 minutes kept it running well and there were signs of oil on the valves and in the cylinder every 10 minutes kept it running well and there were signs of oil on the valves and in the cylinder. No carbon evidence in cylinder.

 

 

Copyright 2003, Florida Association of Model Engineers, All rights reserved.