Fuel consumption study pre- and post-ethanol

[jhwelch]

I've been curious how fast my motor uses fuel and also how much worse
my fuel consumption is with the new ethanol fuel, so I went through my
records and made up a little table for my travels between the same
two points in MA and FL.

Date    Consumption     Engine hours     Gallons/Hour
2004 N      316.24          283.7           1.12
2004 S      308.3           260.4           1.18
2005 N      307.4           307.4           1.11
2005 S      285.25          277.5           1.11
2006 N      277.3           275             1.04
2006 S      329.65          276.8           1.19
2007 N      334.2           290.0           1.15
2008 N      318.66          286.7           1.11
2008 S      266.7           269.9           0.99

2006 N is noteworthy because I had an adjustable main jet installed for
about the first 10 days of the trip. I may also have missed one or two
gas stops, so the consumption number seems a little low

2006 S is the first time I was using ethanol.

Variations in engine hours can be accounted for by boosts or reductions
by wind and currents (I'm always motoring and sometimes am also to
have the jib out).

2008 update:
My trip north this year was with my old engine. I arrived home and
almost had 6,000 hours on it since the last rebuild. The data for the
trip south was with a different engine, newly rebuilt.

-jonathan

[Don Moyer]

Jonathan,

I presume you mean gallons per hour in your last column. Most of our intracoastal cruiser customers with an adjustable main jet are able to lean out their mixtures to get comfortably below one gallon per hour fuel consumption.

Your suspicion that Ethanol fuel may produce worse fuel consumption may turn out to be true; however, you did have one trip where your consumption was essentially the same.

Don

[Administrator]

I found this on a US Department of Energy website:

Performance

All auto manufacturers approve the use of low-level ethanol blends. Ethanol blends (10% or less) are successfully used in all types of vehicles and engines that require gasoline. From a consumer perspective, there is no noticeable difference in vehicle performance when low-level ethanol blends are used. Because there is a slight difference in the energy content of ethanol and gasoline, there may be a slight reduction in vehicle fuel economy when using ethanol.

[MikeB.330]

With a between 50 and 80 hours on a fresh Moyer Marine A4 an am using just under 1 gal. per hour. My new hour meter shows 13 hours since my last fill up. Tonight I put a little more than 12 gallons back in the tank. I had at least one hour on that tank before I installed the hour meter so is more like 14 hours and 12 1/3 gal. of gas. My engine is running lean on the top end though. Too lean me thinks.




Mike