Fuel mileage for 1979 100hp johnson

[reeltime170]

I have a 1979 100hp johnson 4cylinder on a 15 foot cobia, and was wondering if anyone could tell me what the typical fuel consumption is. just bought the boat, and am curious as to what i can expect.

 

[Silvertip]

Re: Fuel mileage for 1979 100hp johnson

10 gallons per hour at wide open throttle. MPG can be calculated based on the speed WOT gets you. MPG at anything less than WOT is strictly a guess and the only way you can pinpoint "exact" MPG is with a fuel flow monitor. As a wild guess, 3-5 MPG.

 

[reeltime170]

Re: Fuel mileage for 1979 100hp johnson

Thank you, very helpful info

 

[airshot]

Re: Fuel mileage for 1979 100hp johnson

I had a 1979 70 hp a number of years back, great motor. We averaged 6 gal per hour at cruising speed 24/26mph. And yes almost 8 gal per hour at WOT on 18 ft alum.