Starting issues after sitting

[mlaird]

ive got a 75 auto pretty much all original. can always get it started, but after it sits for a few days it takes a good 6-10 key turns and me pumping the gas pedal a bunch to get it to turn over. once its running i dont have any issues

to me it seems like it just takes forever for the gas to get to the carb when its been sitting for a day or two. any suggestions on how to fix this? ive got a rebuilt motorcraft carb

 

[gtnorga]

How old is the fuel pump?

 

[mlaird]

bought a new mechanical fuel pump a few months ago

 

[cbford]

When you take the air cleaner off and open the throttle does it squirt gas down the venturi? If not it is a carb issue.

Or, it could still be leaking down with a new pump. Do you have an inline filter between the pump and carb? If not, put in a see through filter and see if it stays full.

Or, it could be leaking out of the carb onto the manifold if a seal is leaking or down the venturi if a float valve is leaking.

 

[mlaird]

carb is a newly rebuilt original

 

[dave67fd]

Also check how your fuel line is run. If run along a hot area you can have a bit of vapor loss after shutdown. Second the visible fuel filter. Rebuilt carb could still have issue. Talk to your rebuilder, he may have ideas as well.

 

[jw0747]

what is your ignition set-up probably Duraspark. maybe need a new ignition module. need new plugs and wires? are plugs gapped correctly?

 

[pcf_mark]

Hmm I am going through something similar now. I replaced every piece of ignition from points to plugs and it did not solve it. I swapped to a junkyard carb and it went away. I swapped it back (it has the kickdown for my AT) and it came back.

I know it is the carb. After it sits it is very hard to start. When I look into the throttle blade the squirters do not squirt. If I crank the engine a bunch of times the squirters start working and no more problems.

Because of this I do not think it is the fuel pump or the fuel line. I think it is the rubber diaphram behind the accel diaphram not letting fuel in or letting it drain out while it sits.

Once it sits look in the carb and see if the squirters are working.

 

[carmi]

It's probably just the fuel boiling or evaporating out of the bowls. I have always had problems with this. After you turn off the motor, the fuel sitting in the carb and fuel lines expands due to the heat and trickles into the manifold. Once everything cools off, the fuel that was pushed out of the carb is now replaced with air. The continual cranking before it starts is just filling the carb to a level that will allow it to run. To check, peel the top off the carb after a few days of not running and see it there is any fuel in the bowls. If they're empty then you have found your problem. I was able to minimize the boiling by putting a carb isolater between the carb and the intake manifold. In addition, wrap the fuel line from the pump to the carb with a heat blocking wrap.

 

[broncobilly72]

FOMOCO carbs: I call it post nasal drip!!!! they all seem to drain the gas out if they sit for a while. I have a 68 ford truck, a 66 mustang and my bronco all did the same thing untill I rebuilt the bronco and changed the carb to a four barrel.

 

[half cab]

Mine crankes fine when cold,just turn the key and don't hit the gas and it fires up.Make a quick stop somewhere for a few min. and fires back up,but set for about 15-20 min and I have to hold pedal to floor to crank(acts like it's flooded)?Just started doing this about a week ago?