The pretty please help me tune my carb thread

T

trenlong

Member
Hello,
I am not sure if I should have put this under the 23xx thread or if it was ok for me to start a new thread but here it is.
Let me start this by saying I am mechanically challenged. The point of me rebuilding my engine and doing all this stuff is to learn so that is what I am trying to do. If I seem dumb that is because I am=)
onto the carb:
the engine is a 266 just rebuilt (new pistons, cam, valve grind, ect, ect.
It has a dui dist with live wires that is brand new
all the electrical seems to be in order, we are getting 12v to the dist.

Now here is where it gets fun. The carb I think is missing some parts. When I bought the truck this carb was on and the guy said it was pretty new just was missing the throttle spring.
When the truck starts up it idles fine, but whenever you give it some gas it will bog down and die. Now the exhuast is not hooked up right now its just going through the manifolds. And we have not broken in the engine, and the radiator is not hooked up so that very well could be the problem but I wanted to get the carb as dailed in as possible before the radiator shows up so that hopefully I can get it on the road shortly after the rad gets here.

So here are the pics
front:
front.jpg

Back:
back.jpg

Right side:
right.jpg

Left side:
left.jpg

And top down:
topdown.jpg


I have no idea what the jets are, I am at about 2800 feet for what its worth.

Now am I missing any parts of the throttle assembly?
throtle.jpg


This is my vacume advance right? Is that the secondary fuel air mixture screw below it? There is one on each side?
leftvacum.jpg


What is that threaded inlet to the left of the choke?
randohose.jpg


Anyway thanks for look and I appreciate any and all help.
Thanks,
tren
 
Well tren, Mike mayben is the resident carb guru 'rount these parts, and no doubt he will weigh in with some sage words of wisdom shortly, but in the meantime I do have a few answers for you.
Firstly, I don't know if your carb is missing any throttle assembly parts. The fact that you don't have any back pressure from exhaust nor any coolant flow May or May not be contributing to the way the engine is running above idle. I know it's hard to wait, but I think you're putting the cart before the horse a little bit.
Next, the vacuum port you've identified is indeed for your vac advance. Since this is a 2bbl carb, you don't have secondaries...just primaries, but the screw on either side of the metering block is for adjusting your idle mixture.
Lastly, the threaded inlet next to the thermal housing was used to connect a hot air tube from a heat riser that sat atop the exhaust manifold on that side. As the engine would warm, heated air from the manifold was directed through this tube into the thermal housing. The spring inside the housing would react to the heat and begin pulling the choke mechanism open automatically. It looks like this carb was converted to electric choke at some pointwhich provides the same function as the heated air, only much faster.
That's about all I dare comment on with my limited knowledge base. Rest assured, you've come to the right place. Mm has a knack for helpin' kno knuthin' binder bubbas like us make their crotchety mixers situp and beg...even from long distance. Hang in there. Help is on the way.
 
Whatcha got there tren izza bastard built from pieces that ain't meant to go together!

Can't see the list number in yore pic...but from the looks of the main body, I'll say it was a "rebuilt" done by Holley. It's definitely had a re-application of dichromate solution, thus the color, only Holley does that in their reman process. But Holley didn't build that carb in that manner, someone has boneyarded major components onto that main body!!

The metering block is for a much later version of the 2300, thus the idle mixture adjusting screws on each side. Therefore, the throttle body does not match the main body which would have the mixture screws in the rear of the throttle body.

So in essence there is no way to make the carb present an idle mixture, the metering block does not match the main body, and the throttle body don't match nuthin'!!

A "correct" Holley 2300 (oem-style) for a 266 (and a earlier 304) would most likely carry a list of 2977 if a manual choke version, I've got several of those on the bench now in various stages.

Your carb is definitely a "hot air" choke version body (manual choke main bodies cannot be converted to electric choke on these list numbers), and I can see the fast idle adjustment screw peeking out, but it May not have the correct levers and linkage on the choke side to make the fast idle system work, can't tell without removing all that stuff. I'm saying that because the throttle body (with the linkage) does not match the main body and choke system!

The hot air choke has been boneyard-converted to an electric choke cap. But the choke cap is from a Ford-app autolite/motorcraft carb of some model, that is not a Holley choke cap as it has no provision for a ground circuit (two terminals, + and -). And without looking at it on the bench, I can't say whether it will operate or not even if wired correctly, I'd have to see how the bimetal spring is connected to the choke lever, and if it travels the correct direction as it heats. Simply connecting the "hot air" tube to it and converting back to a hot air choke May or May not work, again, that would depend upon how bodly botchinated it is based on the po virus!

The fuel bowl I can see, is most likely not the correct bowl for that metering block and main body, the accelerator pump system cannot operate, no way to "convert", the passages do not line up internally!

The metering block carries provisions for a "ported" spark fitting to operate the distributor vacuum advance. But if none of the major components are matched, that location May be "dead" because it's circuitry is blocked and a "port" vacuum signal point in the main body is not machined.

And I see a super manifold vacuum leak point right now in your pic from the rear to the right of the ac sparkplug rebuildable pcv valve, that needs to be capped or connected to something!

Depending upon the original vintage of the 266, it May have used manifold vacuum to operate the distributor vacuum advance system. That means the original oem 2300 for that engine would not have had a "ported" vacuum system to begin with.

Basically what I see here is a carb suitable only to become a parts donor! I won't shine ya on and say it "could" work...it's just not worth it at any cost to keep scruuin' with it! It would never be "right"!

I see this same kinda boneyard-assembled carbs all the time, another reason why folks post a statement like: "Holley carbs are junk, it's just been rebuilt and won't run!!" but I'm tellin' ya...your's takes the top prize at the moment!

I understand how you are working through the motor upgrade in stages, not having exhaust manifolds or coolant in it won't affect this, except to make sure ya don't run it long enough to get the engine even "warm".

We can help ya with some carb "options", new and reconditioned, but please don't think we're trying to solicit ya! It's just with the current carb, you'll be fighting a perpetual battle that is impossible to win! By the way, I just got home from a two day stretch working on drew's junk, the guy I think you sold that 152/weber carb conversion to!
 
Whew!!!
Wow thanks for all of that info!
I guess that explains perhaps why it runs so crappy.
I do have a Holley 2300 that was sopposed to be the donor carb for that one that has the list of 2977 so I guess I can rebuild that one.

Can the list 2977 be converted to electric choke?

and I see a super manifold vacuum leak point right now in your pic from the rear to the right of the ac sparkplug rebuildable pcv valve, that needs to be capped or connected to something!
You are talking about that barbed outlet right? I can not for the life of my figure out why that thing was on there. I plan to take it off.

So is it a good bet to get a rebuild kit for my donor carb and go ahead with that one? I was reading about the descrepancies with the kits, I really want to get this puppy up and running on tues so I May have to go to the napa to get the kit are there any part number in particular I can look out for?

And you can solicit IH Parts America any time you want. I have nothing but praise for them and they are always my first call whenever I look for parts.

Thanks,
tren
 
A list 2997 can't be converted to electric choke. The main body will not mount the choke housing, and the throttle shaft is capped on the passenger side with no extension. That's needed to mount the fast idle levers. And there is no vacuum provision to provide choke break.

With the 2997, the throttle linkage and the manual choke linkage mount on the driver side. In the "23xx" thread, that first carb pic shows a freshly built 2997 that went onna 266. I have another I'll finish tomorrow, that is going onna nice 266 inna s800 next Saturday, it's currently running a motorcraft 2100 that is not proper for the motor.

Nothing wrong with a manual choke on the older iron, but a hot air or electric choke conversion onna hot air is much nicer to deal with in really cold weather!

That uncapped port May be the feed for the vacuum wipers on that rig...also used in conjunction with a fuel pump with a "booster" vacuum pump built in, that provides a wiper signal for times when manifold vacuum is low such as heavy engine load pulling hills, accelerating from a stop, etc. When tuning an engine which uses a vacuum booster pump, it must be isolated from manifold vacuum temporarily in order to be able to read true manifold vacuum without the "additional" vacuum created by the booster pump.

You can use a "generic" Holley service kit available from any Holley parts outlet, use p/n 37-1543, that's the least expensive route to go. Do not use any napa kit in a Holley modular carb, the needle/seat assemblies they use are shit and you can easily strip the threads in the fuel bowl when installing rendering it useless. And most likely, they will not contain the correct main body gasket. And the retail price on the napa stuff is exorbitant considering the poor quality of the kit!

Drew just did a 2997 last week for his round body t'all. I talked him through all the fine points, especially selecting the correct gaskets to use out of that kit. And that kit contains several parts that you will not use. If drew can do this using a claw hammer and nail puller...so can you! I was very surprised that I could find no flaw in his work on Friday! All I did was show him how to set the idle mixture screws!

And we can talk ya through a reconditioning of your 2997 right here if ya just take your time and follow instruction...ain't hard to do, just takes careful attention to detail to be successful!

You will also need two cans of carb spray, I use that wallyworld housebrand stuff exclusively! It's only $1.08 a can local and is the best I've ever used. You can clean the parts without dipping/soaking but it takes a lotta elbow grease to do so. Many times, I run these things through a dishwasher.

If you want to try this, then post a new thread just for your carb overhaul. That will be very helpful to others and we can point out all the nuances you need to pay attention to and service correctly. And there are many detail differences in these carbs over the years, with different assembly techniques involved.
 
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Man, that's an uglier prognosis than I could have ever imagined. But that's what you can expect here. If there's a way to fix it, you'll learn how. If not, there won't be any smoke blowed up yer fanny. The brutal truth May not be what we want to hear, but it will be what we need to hear. At least you've got a plan b, which has now suddenly become plan a.
 
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