Sven wrote:
In article i4aGb.64$_A5.19@fe10, "Eric H"
wrote:


I'm an inland boater, but seems you are talking about a pretty small motor
for the Pacific. I'd want more than that on any lake in down-state Illinois.
Maybe I don't understand your application, but you are looking at a very
small power source. Not much help against the whims of Big Momma Nature.
Just my $0.02 worth.


I'm just looking for typical hourly fuel consumption of a 4-stroke, 6
hp, Mercury outboard running at 3/4 full throttle.

Thanks,



-Sven


Good rule of thumb for 4 stroke petrol is 1 ltr/hr = 3 HP (or 0.27 US
gals/hr = 3 hp).

The tricky thing is to know how much HP the prop is actually consuming
at 3/4 throttle because HP consumed is NOT linear on a fixed pitch prop.
i.e. the prop will consume more than 3/4 power at 3/4 throttle opening
because the prop will allow it to rev higher than 3/4 max rpm.

1/2 a US gal/hr should get you a fair bit of the available 6 HP so your
guesstimate is probably realistic in the premises.

It might be just as easy to take a short test run on a full tank,
refill after a known time & see what fuel was used, then repeat at WOT
(only for a short time!!! you can multiply the results) to see how much
the engine is capable of using in a worst case scenario & even then
allow a good margin because in offshore water you will definitely use
more even on a calm day:-)

K