93 Johnson 70 burning too much fuel??

[boydog40]

my 70hp on a 15' Boston Whaler with a 6 gallon tank appears to be burning waaaay to much fuel and not even running WOT, just cruising, no skiing, no innertubing etc just riding,have not "gauged" it as far as gallons per hour just seems to be flowing too fast
runs good other than that
no leaking fuel under cowl, no fuel spitting out the throats, adjustments I can make?

 

[kenmyfam]

Re: 93 Johnson 70 burning too much fuel??

Should be eating about 7 GPH at WOT.
Significantly less at lower RPM.
Only way to know for sure is to cruise and measure.

 

[trendsetter240]

Re: 93 Johnson 70 burning too much fuel??

my 70hp on a 15' Boston Whaler with a 6 gallon tank appears to be burning waaaay to much fuel and not even running WOT, just cruising, no skiing, no innertubing etc just riding,have not "gauged" it as far as gallons per hour just seems to be flowing too fast
runs good other than that
no leaking fuel under cowl, no fuel spitting out the throats, adjustments I can make?

That 6 gallon tank should last about 45 minutes to an hour at or near WOT. Longer if you run at cruise speeds, around 4000RPM.

To improve fuel economy first ensure the engine is in good tune: check compression, spark, link n synch. Some low cost tune up items for that motor are replace the inline fuel filter, new champion spark plugs and a good carb cleaning.

Onece you are sure the motor is in excellent tune then you can check that you have the correct prop for your setup and if the motor can be mounted higher on the transom. Also the condition of the bottom of the boat should be clean and smooth with no growth.

After all that she should be running great and giving the best fuel economy that 70 can give. They are very fuel efficient compared to other 70hp carbureted 2-strokes.

 

[CATransplant]

Re: 93 Johnson 70 burning too much fuel??

Is this outboard new to you, or is this increase in fuel consumption something you recently noticed on an engine you've had for some time?

It's really hard to tell if it's using more than it should without some hard numbers. How long did it take to run through the 6 gallon tank, and how were you using the boat during that time? Without that info, there's not a lot we can say.

 

[boydog40]

Re: 93 Johnson 70 burning too much fuel??

according to trendsetter I guess mine is getting the mileage it is supposed to be getting
I had a 16' Whaler with a 65 E-rude when I was a kid and we seemed to ski all day and run hard on 6 gallons!!
current rig is running about what trendsetter has advised
guess Im all wet!! and older age creeping up on failing memory!!