Blew the carb on my bronco...replace or rebuild?

[blamejane]

Gas tank leaks so I only fill the bronco with 1/2 a tank of gas at a time. I'm trying to hold-out till next spring before replacing the fuel tank. What this means is I have to be super careful about NOT running out gas. I'm not always successful and after running out of gas the other day, I hear a POP. Turns out it was my Holey carb. I was told I either need to rebuild this carb (believe it's a 600 truck avenger) or replace it with an Edlebrock 600.

What do you guys think. I don't think I want to rebuild, I'm looking for suggestions for a good replacement. I only use the bronco for running around town. Altitude here is between 3500 to 4500 ft in case that matters.

 

[savage]

I'm heard that when the Holley backfires, it sometime damages the power valve, this site talks about the power valve http://forums.holley.com/entry.php?430-Holley-Power-Valve-Tuning. When it come to replacing some like edelbrock 1406 and some like Holley truck avenger, new they are not cheap, even the rebuild one are pricey. I've rebuilt all my carbs and it was pretty easy, main thing is to clean them good and make sure all the passages are open.

 

[Rustytruck]

Anything you buy new will have to be adjusted and maybe parts swapped for the engine to run properly. Nothing saying your old carb was properly adjusted when it was installed. If you go offroad the truck avenger is your better choice. If you Bronco never leaves pavement then the Edelbroc would be the better choice. This assumes that your engine needs a 4 barrel carb.
Nither of these choices would be installed on my Bronco but given the limits of your choices this is what I would choose.

 

[SHX669]

How do you know you need to replace or rebuild your carb? I've had several of mine "pop- backfire" multiple times for various reasons and haven't had any issues after.
Holleys for at least the last 10 years have " backfire protection " for the power valve.

 

[DirtDonk]

Exactly. They say they're protected, so unless yours was an older carb (can't be if it's an Avenger) then maybe, but it's not supposed to blow the valve on yours.
That said, of course nothing is impossible, and I have heard of even the new ones failing sometimes.

But that's just a single part that does not require a full rebuild to make new again. They used to only cost a few bucks, but nowadays they're probably 40 or 50! Still, cheaper than a rebuild or new.

I love the fact that the Edelbrock/Carter design does not use a power-valve, but as said, they're mostly annoying on the trail or at odd angles.

So what is actually wrong now? Does it still run? How is it acting? What makes them think it needs a rebuild in other words.
If just the pop, but it still runs fine, then leave it alone and drive it.

Paul

 

[blamejane]

Thanks for the thoughts and comments.

I was told that the pop/bang noise I heard when trying to get the bronco to start again (after running empty) was the carb valve. So I'm assuming that's why i have to keep one foot on the gas and one foot on the brake when I come to a stop.

The bronco just wont stay running unless I'm giving it gas. Prior to running out of gas this last time I did not have any problems whatsoever.

 

[half cab]

Wonder would a can of seafoam help it?

 

[Master Chief]

These are links to Holley...hope they help.

http://documents.holley.com/199r10268-4rev2.pdf

http://documents.holley.com/techlibrary_carburetor_tech_info.pdf

http://documents.holley.com/techlibrary_power_valves.pdf Interesting note on this power valve page: If you have a carburetor older than 1992 (or you have experienced an extreme backfire) and expect a blown power valve, use this simple test. TEST: At idle turn your idle mixture screws (found on the side of the metering block) all the way in. If your engine dies the power valve is not blown.

I do not see a dedicated troubleshooting guide but here is a link to their Online Tech Site, https://www.holley.com/support/support_request/

Roger

 

[savage]

Thanks for the thoughts and comments.

I was told that the pop/bang noise I heard when trying to get the bronco to start again (after running empty) was the carb valve. So I'm assuming that's why i have to keep one foot on the gas and one foot on the brake when I come to a stop.

The bronco just wont stay running unless I'm giving it gas. Prior to running out of gas this last time I did not have any problems whatsoever.

I'm sorry but when you said (one foot on the gas and one foot on the brake)It reminded me of Sammy hagars song "I can't drive 55";D

 

[bax]

rebuild. Easy as cake.

 

[jckkys]

It sounds like your saying it won't idle now. That would be a symptom of a blown or ruptured power valve diaphragm. The repair only requires removing the front float bowl and valve body. The power valve can then be unscrewed with an adjustable end wrench. 3 new gaskets, a new power valve and your good as new, for about $35 in parts. The carb can stay on the engine. After working with Holleys for a while you get used to only working on only the relevant part of the carb. They're very modular, and don't require a full rebuild in most cases. If for some reason you need to replace the carb, a smaller 400-500 CFM is better for a 302. A good choice would be a List# 4548 Holley that's 450 CFM, and is designed for Ford engines as a factory replacement. AFBs like the Edelbrock Performers are a little more complicated to mount in place of a Holley because they're a lot wider and the fuel inlet is in the back passenger side. A 1403 500 CFM is a better choice than a 600 if you go that route.

 

[blamejane]

Dang you guys are SO helpful. I knew it was a good idea to post here before deciding.

I did a little research and found the manual for the Holley carb. It is a truck avenger 670. My mechanic suggests the Edlebrock replacement if I decide to go that route. I will definitely look into the small 400-500 cfm (including the 1403).

Never heard of sea foam half cab...gonna look into what the heck that does!

I can't thank you guys enough for all of the personalized information

 

[broncojim2]

Holley

Rebuild it , it's not that hard and easy on the wallet ,new carb is expensive ,

 

[fwilder]

Totally rebuild. I've done two recently and it's super easy. Have your compressor fired up and wear some eye protection.

 

[englewoodcowboy]

Check out national carb. They offer a complete rebuilt Holley for $169 with your core. I used them years ago and they tuned it before it left and it was literally a bolt on and go for me. I know Blue71 has been using them for his and everyone so far has been excellent. Bolt on and go.

http://nationalcarburetors.com

 

[clarrance]

:-*

Dang you guys are SO helpful. I knew it was a good idea to post here before deciding.

I did a little research and found the manual for the Holley carb. It is a truck avenger 670. My mechanic suggests the Edlebrock replacement if I decide to go that route. I will definitely look into the small 400-500 cfm (including the 1403).

Never heard of sea foam half cab...gonna look into what the heck that does!

I can't thank you guys enough for all of the personalized information

You have never heard of Seafoam? If you have a gasoline engine in or on any piece of equipment you own then you need Seafoam. I probably use a case a year around my place. It's the best thing since sliced bread. It's handier than a pocket on a shirt. LOL. With today's crappy gas all carburetors can use some Seafoam every once in a while to keep things nice and clean inside the carb.

 

[blamejane]

I want to go with an autolite 4100 but can't find them. I hear a lot of good things about them so just curious where can I get one of these.

EDIT: I guess I'm just wondering why I only see them offered on ebay and is it a bad idea to purchase something that's not readily available. What do you guys think?

EDIT 2: My mechanic suggested a street demon so wondered if any of you are running this one. Is it better to wait and find an automate 4100? Bronco is in the shop with the old carb out, and so I'm kinda stuck trying to make the best decision.

 

[Rustytruck]

I want to go with an autolite 4100 but can't find them.

EDIT 2: My mechanic suggested a street demon so wondered if any of you are running this one. Is it better to wait and find an automate 4100? Bronco is in the shop with the old carb out, and so I'm kinda stuck trying to make the best decision.

Get a new mechanic. Street Demon is all the wrong carb.

Just rebuild your old carb and tune it and run it until you find the carb you want.

 

[blamejane]

Get a new mechanic. Street Demon is all the wrong carb.

Just rebuild your old carb and tune it and run it until you find the carb you want.

Thanks Rusty, that's a good option and will keep me from making a rush decision. I don't mind waiting for the one I want!

 

[blamejane]

I've found a few rebuilt autolite 4100's on eBay. My problem is that I can't tell (and don't want to just "trust" the eBay sellers opinion) which one is correct for my bronco engine. There are all of these numbers like:

Autolite 4100 1.08 venturi...

some say will work with: C6AF-F, AC,AD,AE,AK,AL,AN,AR,AS,AT,AU,AV,AZ,BA

one says: C4SF B

and another: 260-289 V8 #1225

Some state from a big-block but will work with a small block. That doesn't make me feel comfortable. How can I be sure that I get one specifically from a small block engine?

I checked and my intake manifold has been replaced with Eddlebrock Performer 289. I have a 302 engine with C4 transmission so I need to make sure the carb I purchase works with that.

Anyone have some tips for me on what numbers I should be looking for?

I'm still researching...this is fun stuff!