72 100hp fuel consumption?

[overtheedge472]

I have looked and looked and trying to figure out the fuel consumption
of this motor so I can then purchase the correct fuel tank to keep me going for
hours on the lakes. I always planned on taking a 2 gallon reserve/emergency
can with us but I really would like to get a idea so I can then purchase the correct fuel tank for the boat. I just can't imagine this motor living all that long with a 6 gallon tank.

Any help would be appreciated.

 

[Tacklewasher]

Re: 72 100hp fuel consumption?

You'll use about 10 gallons per hour at WOT. Rule of thumb is 1/10th the HP rating gives your gallons per hour.

I've got a 1980 115 and I've added a fuel flow meter to my boat. At WOT I bounce between 11 and 12 gph. I do about 40 mph so I get around 3.5 mpg (as per my gps plugged into the fuel flow meter).

Running at ~4000 rpm and 30 mph, I get about 4.5 mpg. Seems to be my sweet spot for mpg.

So it depends on the type of boating you do. I get hours of use out of a 6 gal tank. But that's because I go at 30 mph for maybe 10 minutes, then spend hours either on the electric or my 10hp Honda. Then another 10-15 minute speed run back to the ramp.

I carry 2 - 6 gallon tanks and really want to put in a 15 gallon or so belly tank.

 

[overtheedge472]

Re: 72 100hp fuel consumption?

Thank you for your response. I mainly will do so some slow cruising around the lake as my wife loves to take pictures of everything. With some full throttle runs to get to other areas quickly. It sounds like I should be ok with 2 6 gallon tanks or one 10-15 gallon tank.

 

[a70eliminator]

Re: 72 100hp fuel consumption?

I vote for two 6 gal easier to handle and move around for balance.