The Stovebolt Site Forums The Shop Area Engine Shop my gas mileage sucks!

As I stated in my post about tranny options I am driving a 62 c-10 with a 55 235 and a 3 speed from a 57 truck , the engine starts right up, runs great , idles well and so on .So my question is? Is this really normal gas mileage (aprox 8 mpg ) for this truck ? or am I missing something ? I do plan to go with the T-5 some time soon but until then ???

A 1/2-ton only getting 8 mpg isn't working right unless you're driving it real hard.

I would guess 12-16 mpg would be closer to normal with a 235.
Are your brakes dragging?
Is your clutch slipping?
Carb or fuel line leaking?
Tires inflated properly?

The above items are the easy ones. A carb rebuild may be in order. It is possible to get poor economy with a bad carb, and still have the motor run smooth.

How are you measuring mileage? Are you using the dodmeter, or are you using a gps. It is possible that your speedometer/odometer is lying to you.

I would guess the carb could be the big offender , It is an auto choke model that I have rebuilt myself and it does run rich but I was very meticulous about adjusting the float and everything so.... what's left there just isn't much to this carb.

What size tires? How are you calculating mileage?
Your speedometer/odometer could be giving you false info. if the donor vehicle didn't have the same rear end gear ratio and tire size.
cm

My tires are 235 75 15's . I was using my odometer for the miles driven . my spedo is slow by 5 -7 mph at around 55mph. I had my dad follow me on the highway to check the speed but we didn't check the miles driven on his car.

This is a "BC" carburetor, yes?
Are you sure the right (small) check ball is in the power valve?
What thermostat?
Is your exhaust heat working?

This is a bc carb . It wouldn't surprise me if by ball's are al jumbeldy ( he he ). the thermo is 180 degrees , I did instal a thermo guage that confirms this temp. exhaust heat is stuck, I had forgotten about that I am not sure what position it is in.

No need to worry about mileage till you get the odometer fixed. With out a accurate means of checking the miles driven, you are just guessing at mileage. Even with a good odometer, it still takes, at least for me, three or four tanks of fuel to get a accurate idea of fuel mileage. Weather from day to day, route changes, or even fuel stations can all account for different miles per gallon. You need to use the same pump, facing the same direction, let it shut off on its own, and fill to the same level each time you add fuel. This is the only way you will know for sure.

Get that truck out on the interstate that has mileage markers, you need to drive minimum of 10 miles, fifty would be better. Note the start and finish miles on your odometer and figure out how far off it is. At this point, don't worry about the speedometer, it should follow the odometer when correcting.

Since the odometer is gear driven, speed is not a factor, just drive straight and steady. Let use know how it does, we can figure out which gears you would need for the out-put to the speedometer head.

Joe