Gas mileage down

[old-tank]

I spent the last week (about 30-40 minutes every morning before it got hot) trying to figure out why my blue/white 55 is getting lousy mileage.  It is getting 12-13 mpg and the expected mileage should be 14-16 for the same trips.  It runs flawlessly.

Ignition:  plugs and wires good; timing good; vacuum and mechanical advance working; dwell good.

Carburetor:  dry outside and inside even with the electric pump running; rods working as expected; fuel pressure with and without electric pump good; electric pump has become necessary most of the time due to vapor lock and boils the gas out of the bowls when parked.

It is probably the gas.  I found an article dated May1, where the EPA will allow (due to Covid) winter blend gas (max ethanol and butane added) for a month and extensions as needed.  Winter blend boils at 100* F, so my gas is boiling and evaporating while it is parked!  It will get cooler someday and gasoline blends will be appropriate for the season again.

[NTX5467]

Manifold vacuum check?  A road-load air/fuel ratio check might indicate ethanol content being greater?  Idle scfrews need any tweaking toward "richer" for higher idle speeds?

 

It MIGHT be just that particular load of gas from the fuel terminal.  As almost everything is now "splash blended" at the terminal as the fuel goes into the tanker.  Unlike "back when" the oil company's OWN trucks delivered fuel from THEIR tank farms.

 

Have you pulled some fuel out and done an ethanol content test?   Is there an ethanol-free pump at the local Murphy Fuel location?

 

Of course, you can run that tank "out" quickly and put some more in.

 

Just some thoughts,

NTX5467

[old-tank]

Last 2 tanks Shell and Valero...suspected previously before I checked.

[60FlatTop]

If you park it on a level surface can you open the door and make it roll by pushing with your foot?

[old-tank]

1 hour ago, 60FlatTop said:

If you park it on a level surface can you open the door and make it roll by pushing with your foot?

Yes, very easily.

[buick5563]

But not in Park.

😁

[JBP]

(At what point do we tell Old Tank that we’ve been sneaking over and siphoning gas from his Century just to see if he’d notice and start blaming the car?) 😜

[old-tank]

2 hours ago, JBP said:

(At what point do we tell Old Tank that we’ve been sneaking over and siphoning gas from his Century just to see if he’d notice and start blaming the car?) 😜

To avoid injury or death, turn your flashlight on when around the garage.  Then you can read the SIGN.

[JBP]

I can’t multi-task; I’ll spit out the gas! 
 

Then things end up like this clown, trying to siphon gas from his ex-girlfriend’s car...

Edited August 19, 2020 by JBP (see edit history)

[NTX5467]

Harbor Freight has a fluid transfer pump that runs on 2 D-cell batteries.  NO need for personal suction.  Costs less than $10.00 USD.  Rubber hose for suction side is extra, as are the batteries.

Edited August 20, 2020 by NTX5467 (see edit history)