good day, im a recent owner of a 1980 e350 custom superwagon that consumes 1.7km per liter of gasoline (3.9mpg), I dont think this is normal, just drove it around the city. it has the original 300 i6 engine dual barrel carb and a 3speed automatic and no air conditioning yet. any suggestions? im not sure if the odometer reads correctly as the speedometer acts crazy between 0mph to around 30mph.

 

First, that is a very good looking 35 year old Econoline.

And no, your mileage does not sound right for a 6 cylinder.

If your speedometer is bouncing around, that would effect the mileage, so a true MPG would not be achieved. Not recording true mileage.

City stop/idle/go traffic would cut your MPG's down, but with a 6 cylinder, not that much.

If you have a true know mileage, like from point A to point B, say 10, 15, 20 miles, and check your odometer to that, then you would know how far off your gauge is. Or even mileage markers on a highway?

Other factors would cut into your mileage, like bad spark plug wire, vacuum leak, very high idle. When was the last time a tune-up was preformed and the timing checked?? Plugged air filter?? Extreme low compression??

 

Ok call me old fashioned.....BUT did you check the Air Filter...When did you change the oil last.....What shape is the Dizzy / Spark Plug Leads / Spark Plugs ?
PM me ..... I have all the Ignition parts you need......The rest is exhaust....I will send you on the correct path....

 

i have new air filter, new oil, engine runs good. I suspect that the mixture is too rich, when I hit brakes hard engine stalls, could it be a stuck up choke? exhaust smells gasoline.

what on what MPG should it be for a 300 engine? thanks

 

too bad im from the other side of the earth.

 

Some of the 80's 300's had an issue with screws that hold the carb base to the carb body. They would work themselves loose. When this happened it could cause it to run extremely rich. The problem is, to check the screws you need to pull the carb. The screws go up through the bottom of the carb base. There should be 3 screws if I remember correctly.

Otherwise check the choke and make sure it's functioning correctly. Or the needle & seat in the carb could be leaking.

 

Hi Buckpago,

I'm interested in the 2bbl carb, usually the 300 engine came with a single barrel carb and the gas mileage was excellent. My guess would be that the float in the carb you have is failing and letting the engine flood with gas. Sometimes the accelerator pump on some carb models will leak gas to the outside of the carb.

I would remove the air cleaner canister and inspect around the carb, removing the carb and inspecting the insides would be next.

If you can find out the maker and model of the carb it would help a lot.

suwertehin ka sana
jim

 

How are you checking your fuel mileage? How many KM's did you drive when you filled up and did you do more than one fill up to get an average? I never owned a 300, but I have owned several vans with different engines, including diesel and I have always averaged in the 12-14 range.

 

I agree with Fordman and the other posters....perhaps rebuilding the carb is an option ? Since you have to take it off anyway to tighten those screws...I think I still have one of those carbs lying around ...I had 2 Vans with the I-6.....PM me if you need free parts...

 

Old carburetor float saturated with fuel (foam float) or partially sunk (brass float) or set too low, . . . ???