1968 Car won’t start

[Mosesatm]

It does not even have to "boil away." If you use gas with ethanol, it evaporates very quickly especially if the bowl is vented. On my '55 chevy, the Rochester 2GC was vented full time. All the gas would evaporate from the bowl in four days.

I think the Ford carbs have a little flapper thing over the bowl to keep the fuel from evaporating, but I won't swear to that.

 

[robert campbell]

The "flapper" thing was actually a "float bowl vent" to vent off excessive pressure in the float bowl at idle. It opened a vent on the top of the float bowl area at idle. When the throttle was opened it closed.


The crappy, yet ok, for high compression engines gas we have now a days is prone to evaporation and running the float bowls dry after a few days. That was more than likely what happened to Mike's Stang.

Rob

 

[hatchdog]

It does not even have to "boil away." If you use gas with ethanol, it evaporates very quickly especially if the bowl is vented. On my '55 chevy, the Rochester 2GC was vented full time. All the gas would evaporate from the bowl in four days.

Fortunately I have a local source for non-ethanol premium and that’s all I run in the car. Getting spendy, $4.50+ per gallon on the last fill up. Thursday is supposed to be 90* so I plan to take the car out for a full blast AC, run it hard cruise and then park it for a few days. We’ll see if the problem repeats itself.

Thanks everybody for your input.

Mike

 

[Mosesatm]

The "flapper" thing was actually a "float bowl vent" to vent off excessive pressure in the float bowl at idle. It opened a vent on the top of the float bowl area at idle. When the throttle was opened it closed.


The crappy, yet ok, for high compression engines gas we have now a days is prone to evaporation and running the float bowls dry after a few days. That was more than likely what happened to Mike's Stang.

Rob

Sorry, I'm not following; how does it evaporate out of a closed bowl?

 

[franklinair]

IIRC, when the throttle is at the Idle position (as when you shut down the engine) the vent is OPEN, allowing evaporation thru the small hole on top of the bowl.

Neil

 

[robert campbell]

Neil is spot on!!!

 

[hatchdog]

I took the car out for a run yesterday in 90* heat, a bit of stop and go in the small town nearby and then some 45 mph county roads leading to a 60 mph hiway. Parked it in the garage and popped the hood as I always do. (Been doing this right along to protect the paint on the hood) Plan is to let the car sit for a few days and then see if the problem repeats. My garage faces west and gets the full blast of the afternoon sun. I keep the overhead door closed, open the window and the man door and turn on the ceiling fan to move air around. Even with all this the garage will heat up to 95 - 100 degrees in the afternoon. The door is insulated but the walls are not. One of many tasks on “the list” we have is to insulate and sheet rock the garage but that’s probably a few years away. I’ll report back with the results.