What is a good GPH fuel consumption number for my 4 cyl 115hp Johnson o/b
for sizing a fuel/water separator? I have a choice of either 30 or 60. I
think the 30 should be more than adequate, but not certain. The good news
is they're only $5 apart in price, so I'll probably get the big one just to
have it if I ever need to put it on a bigger engine.

"RB" wrote in message
...
What is a good GPH fuel consumption number for my 4 cyl 115hp Johnson o/b
for sizing a fuel/water separator? I have a choice of either 30 or 60. I
think the 30 should be more than adequate, but not certain. The good
news
is they're only $5 apart in price, so I'll probably get the big one just
to
have it if I ever need to put it on a bigger engine.


My old 70 hp burned about 7+ gal per hour. My current carbuerated old, V6
175 hp outboard burns 15+ gal per hour worst case (fast cruising and/or
heavy load). I consider this major gas hog territory, so I'm thinking
you've got a very large margin of error with the 30 gph. filter. Did I read
somewhere to divide the HP by 10 to estimate fuel consumption for a 2 stroke
outboard?

Grissy

"RB" wrote in message
...
What is a good GPH fuel consumption number for my 4 cyl 115hp Johnson o/b
for sizing a fuel/water separator? I have a choice of either 30 or 60. I
think the 30 should be more than adequate, but not certain. The good
news
is they're only $5 apart in price, so I'll probably get the big one just
to
have it if I ever need to put it on a bigger engine.



The 30GPH filter is more than enough.
Your 115 probably doesn't consume more than 15GPH at full throttle.

A carbureted outboard usually consumes approximately 10% of its horsepower
in gallons. So your 115 horsepower engine would burn roughly 11.5 U.S.
gallons at full throttle.

The four stroke usually burns about 30% less than that and same with the
direct fuel injection like FICHT would burn equal to 4 stroke. The savings
is the stroke no longer allows the unburned fuels to exhaust out and pollute
while it evacuates the cylinder.






"RB" wrote in message
...
What is a good GPH fuel consumption number for my 4 cyl 115hp Johnson o/b
for sizing a fuel/water separator? I have a choice of either 30 or 60. I
think the 30 should be more than adequate, but not certain. The good
news
is they're only $5 apart in price, so I'll probably get the big one just
to
have it if I ever need to put it on a bigger engine.