Hey guys, I will be getting my 79 Bronco Custom in the next few days, traded my old 97 Cougar for it. Here's the question. When I test drove it, it had a near stall/stutter situation when going from closed throttle to slightly open. I'm suspecting the usual things, filters, carb mixture, timing and whatnot. This truck has sat for a while, and the guy I'm getting it from said he did replace the spark plugs, air filter, and cap/rotor. He hadn't replaced the fuel filter, and had mentioned that he thought it was a 4 barrel carb on top, though I haven't looked at it very closely yet, since I know it came stock with a 2 barrel. Anything you guys would typically look for on a vehicle that has sat for a while? I'll post pictures as soon as I can. Thanks for the info in advance!!

 

Can't believe nobody else replied to this thread all day...
I've had a bit off a stutter to almost stall on my rebuilt motor (Too excited, I showed up at the shop before they even got the air cleaner on...) Just need to adjust it, as I didn't give them time to.
Probably just the usual carb and timing adjustments on your motor. Congrats on the Bronco. Oh, and when in doubt, replace the fuel filter. For a couple of bucks, it's worth knowing that won't be a problem for a while.

 

Thanks for the reply! I went to get the truck last night, and the guy selling it figured out what it was. The float in the carb is sticking open, bad enough that there is gas flowing out of the carb. He tried to free it up, but ended up making the leak worse. Looks like I'll be doing a rebuild before I even get to drive it It drives very nicely, very solid for it's age. Let the work begin! Thanks again!

 

Yeah, sounds about time for a rebuild. Did it turn out to be a stock Holley or a 4bbl?

 

Turns out its just the 2bbl, which is fine with me, since I know nothing about working on 4bbl. I'm debating going to a junk yard to find an old carb to throw on while I rebuild this one. Not sure if I'm going to frustrate myself more going that route or not.

 

It'll take a little over a day to rebuild a Holly 2150, a good part of that time spent waiting for parts to soak in solvent. Unless you can find a cheap replacement that actually works from the junkyard, I'd say just jump into the carb rebuild ASAP.

I'm still running the stock 2bbl on my 400 (Good 'ol California emissions laws...). I actually had to go and buy a remanufactured Holley, because there was something REALLY wrong with my old one. Did the rebuild, and it still didn't run well at all. I started thinking it was something else, but everything checked out fine. Put the remanufactured carb off of my '70 360 onto my 400, and it ran perfect. Just couldn't keep it there because I didn't have the spacer plate for the PCV valve (the 335 series carbs PCV runs straight into the back of the carb, without a spacer plate).

 

Well we dove into the rebuild, to find out that it had been recently rebuilt, so we adjusted a few things, and the truck started, but the tube coming up behind the butterflies started squirting gas all over. So now I don't know what to do, I'm in the process of finding another carb, unless I can figure out what is going on with this one. Thanks for the help so far!

 

I'd say worst case, just pick up a Reman from Holley. End up running about $200 with tax and all that, which is no fun, but it means no more carb worries. That's what I ended up doing with both of my trucks. Pays off in the long run.

 

Yeah, I found out I can get a new Motorcraft 2150 from Autozone for about $71, after the core. So I may go that way. I hear a lot of bad things about Holley's, adjustment wise, and off road use, so I'd rather go with the 2150 I think. I found a few things last night that I'm looking into. The one thing that I think will fix the whole thing, is to be able to get the fuel to shut off once that float gets to the top. If it's just the valve that it comes in contact with, I think I can get that for about 7 bucks. But if that's not the only thing that allows fuel from the pump into the carb, I won't mess with it much longer. If this carb is the original from 29 years ago, it may be best if I just replace it. I'm too impatient, I just want to go out and drive the thing.

 

Holley owns Motorcraft, so I always get the two mixed up. Motorcraft is what I was thinking about this whole time. Only $71? Wish there'd been an Autozone in Santa Cruz when I had to replace my carb. Just make sure to bring the old carb with you when you buy the new one. Make sure it's identical, since there are so quite a few different makes of the 2150.

 

Don't buy a remanufactured carb from a parts store. In fact, don't buy anything remanufactured from a parts store. It's something everyone does once, and learns never to do again. If you get a carb from there, you have no idea what kind of machine work has been done on it; you have no idea what the float is set to; you have no idea how well it was rebuilt. Rebuild the original or rebuild one from a junkyard.

As for the off-idle stalling--this is almost always a faulty accelerator pump. The accelerator pump is on the front of the carb. Either it's not pumping, it is ruptured, or it's set too lean. There is a rod that can be adjusted to squirt more fuel per pump lever travel.

As for the float not shutting fuel off--this is a needle valve within the fuel bowl. It is inside the carburetor. When fuel rises in the bowl, the float rises. The float is connected to a small lever on the top. As the float rises, a needle on the other end of this lever goes down. When it is pushed down far enough, it closes off the inlet valve. This is adjusted by bending the lever on the float, which is called a "tang." A rebuild kit comes with a small ruler that is handy for adjusting this. The rebuild kit will also specify exactly what height to set the float to.

Just because the carb is 29 years old doesn't mean it can't be reused. A carb you get from a parts store will probably be even older than that--it will just be rebuilt (poorly). There are no "new" 2150's. The castings were all made 25+ years ago. You just have to rebuild them--but that is what a rebuild kit is for. When you rebuild a carb, you thoroughly clean the metal parts, and replace the smaller parts, which are provided in a rebuild kit.

 

Ok fellas, I jacked around with the float and valve in the bowl last night, and I'm just not getting the problem fixed here. I pulled the bowl and brought it inside, since it's a roasty 11 degrees F outside right now, and I just looked everything over. I'm usually pretty good at seeing the physics of things, and understanding what needs to happen to get the desired results, but this one has me stumped. I pulled the needle & seat out, and blew them out with compressed air, and pulled the float out to see if it was sloshing inside, and it wasn't, and as I tried to re-assemble things, I blew through the gas inlet and worked with the float and that needle to try to make sure things were sealing up correctly, and after some tinkering, I got it to where the float was shutting things off, but it seems to me that it was taking more force than a simple float could provide. I looked the needle over multiple times under bright lights to see if there were any imperfections on the needle surface and didn't see any, and the O-rings are both in good shape. I just don't know what else to look for. I'm about to throw this thing in the woods, but I can't afford a brand new carb, so I resist, for another day. I can go back and get the rebuild kit, but I'm having trouble seeing what good it will do since this thing has already been rebuilt rather recently. Is it possible that the carb is just getting too much pressure from the pump? I don't recall seeing any regulators on my old '78 I-6, but I guess it's possible. If I get a replacement needle & seat, will that take care of things, because if I need to get one, I'll have to special order it, which means no taking it back if it doesn't work. I'm a bit impatient, because I don't like driving my '93 T-bird in this snow, not because of sliding, heck, I do that intentionally, but because of other people (college kids) who don't know how to drive in this stuff. Any suggestions from the pros here? I really appreciate it!!
Scott M.

**edit**
I forgot to mention that I've finally ID'd the carb as a Holly 2300 series if that helps any.

 

Alright, update. I ordered/recieved the needle & seat for this carb. I haven't put it in yet, but I plan on doing so tonight, as long as this snow storm hasn't buried it yet! I'll keep posted on my findings!

 

I replaced that needle and seat, but it did not solve the problem. I have started a new thread to hopefully answer future questions about this same problem. It is titled "Too much fuel pressure??" The truck runs great at an idle, and when there's enough fuel in the bowl, it is powerful now. I replaced a few vaccuum lines, and some of the fuel hose, and the timing is now advancing as it should, and things are great, as long as I can figure this fuel flow issue out. Thank you all again for your help!