Hi:
I have a 1966 Ford F100 with I-6, 300, 1 brl carb engine, 0.030" bored ( engine bought from RAMR of spokane , WA).
My problem is I think my truck drinks alot of gas. I wanted to know first how I can test and see if the engine burning gas regurarly as it suppose to be, second how to improve gas milage. Thanks for your help.

 

what color are the plugs?

 

More important, what mpg are you getting? What you consider high may be normal.
Will also help to know trans and rear axle ratio.

 

Thank you folks for replying.,

Ford390gashog: Autolite plugs, ( I ran Champion but I thought it was the problem), and the color is the normal white.

ddvidv: Not to sure what MPG I am getting, but in a trip of 90 miles(including 13.7 Miles mountain driving to about 7800 feet), it burns 1/2 of the tank.

 

ftrk66 that translates to about 10 mpg and that is not out of line for 40 year old trucks.

John

 

That's make me feel better depite the low milage. Thanks Jowilker.

 

You can go to a smog place and put it on the sniffer, that would give you an idea.

 

Thats part of your problem, RAM has a horrible reputation here in town.....

But seriously, 10 isnt bad, and actually "white" spark plugs are a sign of a lean condition..... they should be a tannish brown color

 

I done somthing this afternoon:

I filled the tank up to 3/4, wrote down the milage (71442), drove till the fuel indicator hit 1/2, checked the odometer (71465), all in the free way.
Can not understand that, 1/4th of the tank burned in 23 miles.

Or maybe there is another way of counting the MPG. Somone could give me a hint.

ddavidv: forgot to tell you, the tranny: 4 speed manual T-18 Borg, and rear axel: Ford 3.70-3.3M.

Icicle: all plugs are carboned black( Ithought you meant the colour of the ceramic casing of the plug).

 

LOL maybe it has a leak somewhere ? check all along the fuel line, do you have a good seal on the cap ? smell gas while driving ? have a kid in the neiborhood who always seems to have gas for that go kart ?

 

Best way to do mpg...
Fill tank till the pump clicks off (yeah, I know, costs a fortune...)
Drive and use at least half. The longer you drive, the more accurate the reading.
Refill tank till it clicks off, as before.
Read gallons on pump. Jot it down.
That's your gallons consumed...divide that by the number of miles between your fuel stops, and you'll know.
Highest you should expect with these trucks is around 15-16 mpg, and that's rare.

 

Then your running extremely rich, and need some carb tuning done.....

fix your rich condition, and your mileage will go up....

using the gauge like your experiment noted isnt very accurate, do as stated, fill it, drive it down at least halfway, and fill it again. and divide miles by gallons used....

good luck!

 

Then how to tune carburetor, I set my carb idle mixture screw as specified in the shop manual and that was 4 years ago, long time, ain't it.

 

What carb is it

 

Ideal around the ceramic part of the electrode should be the color of a toasted marshmallow. any darker and it's not getting a clean burn on the gass. probably mixture, but it can also mean a weak spark, or an engine that is running too cold.

I'm getting 14.5 mpg on the highway at 60. Thats very good for a stock old truck with low gears.

Brand of plugs doesn't matter. spark is spark. What temp does your truck run at? the lower the temp, the lower your MPG will be.