Fuel consumption for a 1975 70HP Johnson?

[Jet Wrench]

OK, took the Whaler out for sea trials yesterday (66 Whaler Sakonnet. The engine ran great through out the power band! I am a bit concerned about fuel usage. What is the average fuel burn at full throttle for this engine used on this type craft? I travelled about 12 miles total and burned about 4 gallons of fuel. This seems a bit high. I did rebuild the carbs on the motor. Any inputs or suggestions are appreciated.

Jet Wrench

 

[johnson89]

Re: Fuel consumption for a 1975 70HP Johnson?

70 (2 cyl)
5,250 rpm
7.7 gal. per hour


70 (3 cyl)
5,500 rpm
7.4 gal. per hour

 

[Jet Wrench]

Re: Fuel consumption for a 1975 70HP Johnson?

Thanks Johnson 89,

I guess I'm not too far off the mark then. I will need to throttle back to get some decent fuel burn. I did set the carb floats per the manual. I don't see any leaks, but I see a bit of residual fuel at the bottom of the carbs. I was wondering if I should set the floats a bit lower than what is called out in the manual to alleviate this?

Jet Wrench

 

[boobie]

Re: Fuel consumption for a 1975 70HP Johnson?

Hey Johnson89. What's a 70 hp 2 cyl and how come these mtrs burn more fuel at a lower rpm ?