Carburetor?

[wdetzi]

I could really use some help understanding or fixing my problem!

I just installed my rebuilt 302, starts and runs fine when cold (has a stock 2 B carb). The timing is set at 12 degrees BTDC. After the engine heats up to normal run temp, the idle becomes erratic and will usually stall out. After that it's virtually impossible to start, and the only way I can get it to start is to hold the accelerator to the floor and when it does finally start, puffs of white smoke pour out of the pipes until it's at it's normal idle speed. When the engine is shut down after it stalls, I can hear the gas "boiling" in the carb and vapor is coming out of the throat. Sure would appreciate any help or insight anyone can give me on this problem.

Thanks

PS: The carb is original, but has been rebuilt with just an off-the-self rebuild kit (gaskets, seals, accelerator pump, etc.)

 

[dtwood456]

I am not sure if I am qualified to even speak on this or not, but I will give you a thought, and let the pros on this site figure it out. I had a similar problem with my 302, and a freind told me to put a new coil on. I have not idea how to properly test a coil, so I bought a new coil, installed it, and it cured the problem. Please ask some of the other guys if they have heard of this helping. I don't know if it is your problem or not....just a thought.

David

 

[Bully Bob]

If memory serves, (which is less & less these days)

the timing is around 6-7 deg. with the junk gas that we get..? <_<

Was the timing chain double & tripple checked on installation..?

Could there be a restriction to coolant circulation as well..?

(Radiator or 'stat) The carb itself should be fine, meaning it's not the root of your prob. B)

 

[Seabronc]

I could really use some help understanding or fixing my problem!

 

[wdetzi]

Well, your symptoms are typical of flooding the engine.  With some carbs this happens extreemly easily.  If you even touch the gas pedal before you start cranking they flood when hot.  A way to live with it untill you have time to fix it is to keep your foot away from the pedal untill you have the engine cranking and then only just touch it lightly.  If you touch the pedal ahead of time the excellerator pump shoots a jet of gas into the intake, (Ok if the engine is cold and sometimes several shots are needed if it is cold enough, but no good for a hot engine.  The hotter the air inside the intake the leaner it needs to be to get a proper air/fuel ratio).  Then you have to hold it to the floor to alow the engine to clear out the extra gas and when it does finally catch on a cylinder or two keep you foot there for a bit .  This is most likely due to the accelerator pump adjustment or an internal problem inside of it.  Your rebuild kit should have had a proceedure for setting it up and adjusting it.  It's possible the gap between the pump lever and the operating lever is too small or non existant.  Also the pump cam should be in the number 1 position for normall driving.  Did you use an aftermarket kit for the rebuild or one built by the carb manufacturer?  What manufacturer carb is it?
As far as the boiling, that says for some reason the carb is getting too hot caused by transfering a lot of heat from the intake manafold.  Do you have the EGR spacer between the intake and carb? If not, the carb may be too close to the intake manafold.  There are a few ways to fix this, like a spacer that provides an insulation (looks like a thick gasket), Stainless steel bolts (they don't transfer heat like standard blots), installing a heat shield (it deflects the heat off the engine around the carb). Another way to keep the intake manafold cooler is using a pan gasket instead of the two individula gaskets between it and the heads and stainless steel bolts (the gasket keeps the hot oil off the bottom of the intake manafold).  This gasket is common in engines that are installed in vans, I use it on my engine to aid in cooling.

Hope that gives you some food for thought.

Good luck,

>-

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[wdetzi]

Thanks Bronco Buddies,

I tried all of your suggestions, don't know which one or all fixed my problem, but she's running like a champ now!!

I rebuilt the carb, decreased the advance to 6 degrees and rerouted and replaces some vacuum lines. All's well in my Bronco land!!

Thanks for your help and suggestions.

Bill

 

[Broncoholics]

Thats great you fixed the problem but sucks you don't know what fixed it.

To bad you didn't do one at a time and test so you know in the future whats going on. I guess if someone else has this simular problem we can try all the option listed above but damn!

 

[wdetzi]

Thats great you fixed the problem but sucks you don't know what fixed it.To bad you didn't do one at a time and test so you know in the future whats going on.  I guess if someone else has this simular problem we can try all the option listed above but damn!

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Sorry about not explaining the fix correctly!! I found out that I really had two problems - first the carburator rebuild really fixed the problem of fuel "boiling" after I shut down, the hard start problem or rough idle and stall was fixed by adjusting (retarding) the timing from the 12 degrees to 6 degrees. Hope that helps others with a similar problem.