On my ranchero ( 70 -351c with edelbrock 1406 carb, with new stock type fuel pump, new edelbrock fuel filter) After it sits for a week Its super hard to start up. Its like all the gas is gone from the carb and line. after cranking and pumping the pedal, it will finally get gas. but if I drive it everyday its fine. why does it leak down so bad after a couple days?
The fuel evaporates from the carb's fuel bowl My 65 is the same way-----If I drive it every day or two---fires right up If it sits for any length of time-----takes a while for the fuel to get to the carb. It has now been sitting 3 weeks---should be fun to start this morning. I think it has something to do with today's fuel. I used to let my old C-10 sit for days on end and it would fire right up. Not so with any of my carbed cars now
The alcohol they are diluting the fuel with has a lower vapor point so it evaporates a lot faster than gasoline. Also it absorbs water from the air so when it evaporates it leaves behind a gasoline/water mix that has to get flushed thru the cylinders before the car will start.
Both my rancheros do the same thing. Sit for more than 2-3 days have to crank them up a bit to get fuel back in the bowl. Some guys have installed an in line check valve that allows fuel to flow in one direction. That I could see working for a car that sits a week or two. But more than that I think ribald is right evaporation becomes more of an issue.
If you have a vehicle that is not started regularly it is advisable to add a fuel stabilizer that is rated for alcohol blends in the tank. It will help with this problem, and prevent the really nasty problem of the fuel making a phase change in the tank requiring a complete flush. The phase change requires exposure to air, but many older cars do not have an evaporative control system that prevents access to outside air like modern cars have.
Ethanol blends are a horrible fuel for carburetor style systems. Pump fuel is not made for these systems. Don't know of any new production car made with a carb. Ethanol free fuel is available in some areas and it may help the problem. http://pure-gas.org/
Try this , get it started and turn it off before it gets warm but to where you know it runs, then let it sit for a while if it still runs out of gas you must be leaking out, if it starts again then I think that the fuel is boiling out of the carb while it is turned off due to the cross over passage in the intake and you need to put a heat shield or thcker gasket under the carb, have accutually seen it get so hot the fuel will start to boil right after you turn it off, put a phenolic spacer under the carb and it did not do it any more.
No Gas One of my buddies that has a early 70s Ford Pick up finally went to a electric fuel pump and it works great. We live in North Illinois and it doesn't matter how long it sits or how cold it gets it fires right up. He has a 351c in it as I do in my 71 Ranchero. man-o-man I've been tempted to convert but I'm to much of a originalist. Good luck if you go that way. Bil
Convert to a holley blue electric fuel pump run one on my built cleveland stroker that is pushing 560 crank hp and I have never had any issues. Also if you do it wire it up with a relay to be easy on the electrical system, and also run a oil pressure saftey switch still have to put one on mine.
and also run a oil pressure saftey switch still have to put one on mine. >rd ++++++++++++++ How are those wired? What I'm wondering, the motor before starting has no oil pressure, so presumably the switch would be deactivating the fuel pump? So if there's no fuel in the bowl [the problem of this thread] then how is the motor started to build pressure? There has to be a way around this, but I haven't seen it described.
yeah I thought of the heat issue, and I added the spacer last summer, and added the eledbrock hard line coming off the carb to keet the fuel away from the intake. I also went with the braided stainless hose to that from the fuel pump, to help insulate that. I guess its just evaperating. Ill have to try that fuel stabilizer, if that dont work Ill go with the electric fuel pump idea. thanks guys.
electric pump OK now I know my buddy Joe didsn't put any oil pressure switchs and I don't aregue with anything that makes it more fail safe. He did hook it through a relay, buts lets not make this a spend a ton of money and time on. All I can say is when its 10 above -0- here in North Illinois his truck fires right up. Shakes and rattles for a while but so do I at 10 above.
i had this problem for a while....then it got so bad that it wouldnt crank in cold weather at all...or any weather without adding a splash of gas to the carb .....replaced my carb instead of a rebuild and i can let it sit 2 weeks now and it cranks immediately!!! Not saying you need a new carb..just that if it gets worse you prolly need a rebuild to seal things up a bit better.
On fuel injection systems the computer over rides the oil pressure cut off for a few seconds to allow starting. On an older system you just have to use a 'delay on' type time delay relay on the oil pressure switch.