7 replies to this topic

[stinger]

85 with a carb any computer controls? well i dont have puter controls on my 85 with a carb maybe that the in gear idle is to low.

[sweepersrgr8]

The 2bbl is your problem. I've never seen a 460 with a 2bbl, didn't even know Ford produced them.

Unless it's a feedback type carb, you won't have a MAP sensor. Your idle should be around 650 RPMs in drive, but you have to take the engine, and any modifications into consideration. After the timing, and carb is set up properly, I would set the idle 50 RPMs below where the truck starts to creep forward on its own.

If I were you I would go back to the 4bbl. The Motorcraft (Holley) 725 CFM was the most common one that Ford use on the 429/460. If you look at the 2bbl you will notice the primaries are almost as large as a 600 CFM's secondaries, but it has smaller jets, so you are probably just leaning out too much when you put the truck in gear. The primaries on a 4bbl are smaller, and the jets are changeable to fit your application. As long as you keep your foot off the floor, you will get better gas milage from the 4bbl, but the extra power will be there when you need it. An out of the box 750 CFM Holly should put you at a good starting point.

[Seabronc]

Assuming that this is actually a Bronco, my first question is, are you sure this is a 460 ? Bronco did not come stock with a 460, so if it is, it must have been installed later and I can't immagine someone swaping in a 460 and leaving and putting a 2 bbl on it. The 351 did come with either 2bbl or 4bbl and I wouldn't have either engine with a 2bbl, just my preference .

That being said, with a non computer controlled engine, Duraspark II, a couple of things that will cause that type of stalling are vacuum related and choke. If you let it come up to normal operating temp, will you be able to run in drive and reverse ?

Definately do a tune up. Then set the idle speeds. When at normal operating temp, disconnect and plug the distributor vacuum hose, put throtle on the highest cold idle step (rpm for this step should be approximately 2100 RPM), if not adjust the cold idle screw to get that. Reconnect the distributor vacuum and set your curb idle screw to approximately 1600. Fot on brake, put in drive, idle speed should be approx 650. If it starts to stall, put back in park and bump the curbe idle up a little. Repeat untill it idles in gear. Like Sweepersrgr8 said then add approx 50 rpm.

The choke either not opening or opening too soon will also give this type of problem. Assuming it is an automatic choke, check the position cold and then watch to see that it opens. It should be fully open with the engine warmed up. If it to comes off too soon it will give a similar problem. A lot of people go to manual choke to resolve this, but it can be adjusted properly with a bit of patience.

How about posting a picture of the engine. like they say, "A picture is worth a 1000 words".

Good luck,

[hawk2100n]

hey seabronc, you have the same carb on you 351 as me. do you have manual choke. i set the choke for startup and bump up the idle with my foot, i have to let it warm up for a minute and then i can go. usually only fall, spring and winter. do i need to adujust my carb? do you have a similar startup procedure. also, this is only in the morning or the first drive of the day. if i dont drive it early, like on the weekends, it wil start a little easier but not mutch. any adjustment necessary. thanks

[Seabronc]

I'll PM you with what I went thru with mine. But the basic answer is most likely.