how much is too much . 70hp 74 Johnson

[blueboat1]

I have a 17' aluminum v-bottom, a 1974 70hp Johnson. Load = 2 batteries, 12 gals fuel, bait tank, tackle and 2 people. At WOT back off about 20% and run for 1 hour. It will suck a 6 gal dry. Is this normal? I have run a 14 pitch (25 mph) and a 17 (34 mph ) it didn’t make any diff except top speed. Speeds measured by the speedometer on the boat so they may be off) <br />I know of no adjustments besides a properly tuned motor and tilt/trim to control the amount of fuel burned . any tips on better fuel burn as far as tunning? I could even lose a little power and not mind if i gain FPG (fish per gallon)<br />Thanks all and hope you had a great weekend!!<br />SCott

 

[Chinewalker]

Re: how much is too much . 70hp 74 Johnson

With the 17-inch you're getting approx. 34mph, which works out to almost 6-miles per gallon, which isn't too shabby for a boat...<br />- Scott

 

[ajp]

Re: how much is too much . 70hp 74 Johnson

That seems a little much if the engine is a looper. Is the engine a crossflow or a looper? We use to ski behind a 1980 70 hp Johnson looper engine. We would use a tank a day, but there was alot of idling around picking up skiers, but still several hours of running.<br /><br />I have a 1969 115hp Johnson crossflow that will use a tank in a little over 2 hours, running some WOT and then just idling around picking up and baiting juglines. Those old crossflow engines are not the most efficient.

 

[blueboat1]

Re: how much is too much . 70hp 74 Johnson

It's a looper. runs great i guess i am just use to 10 years with a merc 9.8 and a rude 6.0 on small aluminums where 6 gals was a fuel (full) weekend of fishing. come on fuel cells!!! i need some range.<br />Thanks for the input<br />Scott