to carb? or not...

just a quick carb question. my 74 has the 304 w/ orig 2bbl motorcraft. Good jeepin buddy hooked me w/ a holley.(zip,zero,nadda).
The facts....orig has idle problems, cold start is great, I tweeked that and it starts like a champ. kick down is good but low idle is either to high or stalling... cant find a happy med. no air leaks that I could find... the new carb needs some mods to work.... gov has to go and the linkage is huge. Maybe a generator carb??? I was told to pull the bottom plate (6 srews and save the gasket) and use the orig linkage.. any thoughts????

 

It's great to get a free carburetor... you may want to put a little more effort into the Motorcraft 2100 though. The usual failure for the Motorcraft carburetors is a bad power valve. The power valve is located under the carb body under a cover with 4 screws.

The 2100 is a lot better off-road carb than the Holley. You need to do a lot of parts swapping to make the Hollley run as well as the 2100 does on hills and side angle.

 

I favor repairing the 2bbl carb on the Jeep
they are quite simple and reliable IMO
the Holley would be a question mark to me
too much trouble to make it work, and .....
seems the Holley repair kits cost more $$ than they are worth

 

decision made.... since I'll be going in sould I grab a carb rebuild kit and just go for it? Also is the power valve part of the rebuild kit or a sep item? you know how that works some times. Thanks again.....

 

most kits from parts store won't have the power valve....check with them
however, Holley sells power valves individually thru speed shops, etc. They are a direct replacement in the Motocraft carb.
they are rated by inches of vac; I would think a 7.5 or 8.5 would work; what our shop used in the past, ymmv.
When you remove the cover on yours, if you have gas in the cover, then you know the valve is bad

 

Jim,

Would the same power valve be used at 7000 feet or is there a different one for that?

 

hmm
good question
I thought about mentioning that issue above.
a factory Motocraft (2DA2, etc), power valve opens at about 6"-7" of vac.
power valve helps to increase fuel for engine enrichment at full throttle/low vac conditions. The jets actually control/meter the fuel. I would say the range of the power valve would work fine at 7000 feet.
Maybe someone more experienced with high altitude carbs could explain better than me.

 

I think I've bought 3 kits for the 2100 in the last couple years, and they came with power valves. You can buy them separately at speed shops or at online stores like Parker Carburetion or Summit. The Holley and Motorcraft powervalves are identical.

Carb kits usually have an inner celophane package so you can inspect the contents without breaking the package seal.

Here's a picture:


The power valve on the left is a one-stage valve (ca $5) and the valve on the right is a 2-stage valve (ca $20). Later Motorcraft carburetors use the 2-stage item. The carb on my pickup, from a '79 Cherokee, has a 2-stage valve.

Holley has some instructions on their web site re power valve tuning.
http://www.holley.com/data/TechService/Technical/power_valves.pdf

 

contacted local speed shop, he didn't know you could use a holley in a motorcraft. said he could match up the numbers. I've use 4wd for misc parts before. Will try to contact them on the rebuild kit w/ powervalve. may do an exploritory on the holley I got. will post pics if I get into it.

 

No need for a specialty supplier for your carb kit - your local Napa or such will have it or can get it.

I've heard that Holley made the Motorcraft carbs, but I have no way to confirm that.

 

found this site w/ some good info
[http://www.advanceautoparts.com/english/youcan/html/pht/pht20020301cr.html#Of Jets & Floats]
most shops are closed. thats what I get for being a weekender.
Finish brakes on the ford, do a radio for family and a couple of :stout: . It'l be monday before you know it.

 

Dave, you mentioned this "split the linkage" before. I'm not sure what you're thinking. The Motorcraft won't come apart like the Holley. In my experience, none of the Motorcraft linkage stuff will fit the Holley, or vice versa.

 

the guys who gave me the carb are top notch mechanics, But the spray out so much information its tuff to keep up. my buddy was looking at the holley and said the linkage looks way off. which it is. His quick thought was to sep the bottom plate w/the original linkage from the motorcraft and plant the top of the holley on that. His idea may have ben quick and not completly thought out. But I was happy to have a pretty fresh holley in my hands anyways. he said pull these six screws. here,here and here and your good to go. and me being the brain child said "no problem" and here I type.....I'll keep doing the three foot schuffle till I'm ready to dive in or when winter sets in.

 

That's kind of what I thought. The M2100 will not separate like the Holley. The entire body of the carburetor is one casting - there is no bottom plate. To take the linkage off of the M2100, you need to remove the throttle plates and slide the throttle shaft out. Don't remove the M2100 throttle plates unless you have to - it's not meant to come apart easily like the Holley.

 

A little late with the update. Ordered rebuild kit monday ,due today. Kit comes w/ powervalse. Cost of valve is half the price of the complete kit. As they say go big or go home... thanks for all the help will start another thread when I get to that point. For now I'll run the hell out of her.....besides REDSOX are on and the Yankees are comming to town this weekend... GO SOX!!!!!!!!!!!!!!!!!!!!

 

I just rebuilt my Motorcrap 2100 a few weeks ago and the kit contained a new power valve. The kit brand was Sorensen.

 

Go Sox!!!!!

 

Not that much of a Sox fan (being a displaced Angelino), but playoff baseball is great. Best single reason for having cable TV.

 

Good news and bad News. Sox Won in huge fasion last night, the Yankees are coming to town, and my rebuild kit is in...(Echlin) is the brand. Bad news.. My f150 clutch slave cylinder exploded, Just got delivered off the hook two minutes ago. time will be devoted to clutch,rear main seal, master and slave cylinder and hopefully not a new fly wheel. Don't forget the gravel driveway. Sounds like the sox are on the radio and my backs in the dirt... I'll keep you updated on the carb..