292 Monojet carb help needed

[Auston]

Hey guys. After life getting in the way the past few months, I’m finally getting time to get back on the truck. It’s a 71 c10 with a 292. It’s got a Rochester monojet that the original owner took all the choke stuff off. What am I missing?
Truck idles great but won’t take the fuel trying to drive it. I know the choke isn’t going to help this issue but while I’ve got it off trying to clean it, I might as well fix the choke issue. I’ve attached a pic to show you what I’m working with, or lack there of.

[Rust_never_sleeps]

Not a monojet guy, but here's some pretty pics of the choke system and info:
https://www.carburetor-parts.com/Mon...em_ep_780.html

Tech info here, and you can buy parts there:
https://www.carburetor-parts.com/monojet-technical-help

[Rust_never_sleeps]

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['68OrangeSunshine]

My '68 C/10 Stepside came with a production RPO L25 [292]. In nearly 407k miles, I'm on my third 292.
The '68 used a Manual Choke, Knob on the dash thru a cable into the engine bay and cable end directly to the choke butterfly.
Not sure if by '71, they got fancy with electric or automatic [ heat actuated bi-metal strip].

I moved on from the Monojet in 1978, going to an Offy intake and four barrel carb, but I kept the Manual Choke.

I also have a '71 GMC Jimmy with a V8 350. I added a Manual Choke to this truck. It wasn't hard. I had to drill a hole in the Dash, under the Wiper switch, and route the Choke cable thru it. When you remove the plastic instrument panel, you will see there is already a hole on the metal of the Dash for it. And a reinforced plastic disc for a Choke molded onto the back of the Instrument Panel.
Knob, Cable and Bezel are available from 67/72 parts vendors. If done right, it looks Factory.

I live in Arizona, and wildly different elevations and climatic conditions can be experienced in the course of a day's drive. The Auto Choke going off at the wrong times annoyed me.
The Manual Choke is there whenever I need it, but not when I don't.

Your fuel delivery problem might be due to a bad Fuel Pump.

[Auston]

It’s definitely got the automatic choke or the one that runs off the exhaust manifold. Would love to keep it the way it came but if it’s a bad system, it’s a bad system. I really don’t like drilling holes.

['68OrangeSunshine]

Originally Posted by Auston

It’s definitely got the automatic choke or the one that runs off the exhaust manifold. Would love to keep it the way it came but if it’s a bad system, it’s a bad system. I really don’t like drilling holes.

You're only drilling one 1/2'' hole in plastic, that's already marked out for the Factory Manual Choke option. * Only an expert will be able to tell the new choke is aftermarket by the lack of a plastic CHOKE label. Add on CHOKE labels with a hanging hole for the shaft to run thru once existed. I had one once. I don't remember where its got to. And they aren't visible in any catalogs I've looked at lately.
Instead of two knobs on the dash, you'll have three.

*When you pull off the plastic instrument panel, you will see four metal supports, two on each side, existing in the Dash metal. On a '71 only the top ones are used; LIGHTS on left, and WIPERS on right. The ones below are for Choke and Manual Throttle -- which if you don't have a PTO Winch, you won't need.
'67 and '68 have Wipers on top, and Lights below on left, and Choke on right, [Manual throttle if present below.]

[Steeveedee]

Auston, the divorced choke is there, attached to the exhaust manifold. That hole in the air horn tells me that the shaft and flap for the choke are gone. Or maybe I just need a view from the top? But I don't see that shaft sticking out; it would have two flats on it for the lever that attaches to the rod from the thermostatic choke coil.

[Auston]

The butterfly is there, attached to a spring on the opposite side. I’ll get better pictures tomorrow.
Btw, how hard is it going to be to clean this thing? I’m a small engine mechanic by trade but have never messed with a carb this big.

['68OrangeSunshine]

Originally Posted by Auston

The butterfly is there, attached to a spring on the opposite side. I’ll get better pictures tomorrow.
Btw, how hard is it going to be to clean this thing? I’m a small engine mechanic by trade but have never messed with a carb this big.

To clean the Carb or the Engine?
You can spray the engine with Engine Degreaser from the auto parts store. Let it soak 10 minutes, then spray it off. Put a plastic bag over the carb.

To clean the Carb, you can shoot it with Carb Cleaner spray, outside, then inside with it running. If it stumbles, let catch up.

For deep cleaning buy a carb kit for a Rochester Monojet. And a quart can of Chemdip. Take the carb off. Take pix of how it's connected before that. put the carb in the can in sub assemblies, and soak. You might have to brush out some small cavities with a toothbrush. Clean all the small parts and dry them. Wear rubber gloves, don't get this stuff on your hands.
Reassemble in reverse order.

[Steeveedee]

If you're a small engine mechanic you're going to appreciate the bigger pieces! These carbs are dirt simple.

[Auston]

Originally Posted by Steeveedee

If you're a small engine mechanic you're going to appreciate the bigger pieces! These carbs are dirt simple.

That’s what I was hoping. Just making sure there wasn’t anything funky I needed to watch out for or get out of adjustment.

[Auston]

Here’s some better pictures.

[Auston]

More pictures

[Rust_never_sleeps]

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['68OrangeSunshine]

I'm not really on a crusade for Universal Manual Chokes. Sometimes the Devil you know, is better than the Devil you don't know. [Old South African Proverb.]
If you can repair or replace the BiMetal-actuated autochoke, then go for it.

[yuccales]

Lot of good info here.

https://www.carburetor-parts.com/Mon...jBr4Inm9Sd3REY

[Auston]

So I’m assuming my choke shaft is broke? Or I’m atleast missing some parts.

[geezer#99]

Originally Posted by Auston

So I’m assuming my choke shaft is broke? Or I’m atleast missing some parts.

Or you don’t have a divorced choke carb.
Looks more like a manual choke carb that’s missing the cable and spring bracket.

Nice pics in here.


http://67-72chevytrucks.com/vboard/s...d.php?t=505992

[Auston]

I’m assuming it’s got a divorced choke or whatever since it has the rod attaching down at the manifold. There’s got to be a piece of the choke shaft missing. What else would that rod attach to?

[geezer#99]

Another thing your carb doesn’t have is the vacuum break diaphragm that’s needed for a divorced choke.

[Auston]

That’s what I’m asking. What am I missing? Can these parts still be bought?

[RichardJ]

I agree with geezer that it looks like a Manual Choke Carb, but the fast idle linkage is missing or not visible in the photos. The throttle return spring should not be connected to the choke linkage or any other part of the carb.
It may be a simple carb, but there are at least 200 versions of the damn thing.

[Auston]

Great. I know the return spring for the choke plate isn’t in the correct spot. I wonder now how he was choking it. Unless he wasn’t.

[Rust_never_sleeps]

Originally Posted by Auston

Great. I know the return spring for the choke plate isn’t in the correct spot. I wonder now how he was choking it. Unless he wasn’t.

Warm areas, some folks just lock the choke wide open and fast idle it with their foot for a few minutes, or leave a brick in the car ;-)

[Auston]

We’re in southeast Alabama so that would make sense