choke on 4160 adjustment
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Senior User
Joined: May 2004
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From: Colorado
choke on 4160 adjustment
I would like to thank everyone for their help so far. This Holley is eatin me up. The choke was not connected before I rebuilt the carb. Now it is. When the engine is at op temp, the choke flap on the tower should be closed correct? Next, when the truck is running at op temp, the exhaust smells like it does in the morning. You know, that strong exhaust smell. Kind of gassy. It does not smoke. Could this be from the choke or my carb adjustment itself. I'm starting to feel bad for the people sitting next to me at a light. It is not an electric choke. Also on the passenger side behind the choke is a threaded male opening. Should I block this off? The truck does not have the original air cleaner assembly.
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Choke is to be closed when cold and open as the motor warms and fully opened when the motor is fully warmed. In fact, before it gets to fully warmed. The purpose of the choke is to restrict the volume of air entering the motor and thus richen the air/fuel ratio with a higher fuel component.
If it is still closed after warm-up then the motor is going to be running way too rich and thus cause the foul exhaust odor.
Good luck,
Mark
If it is still closed after warm-up then the motor is going to be running way too rich and thus cause the foul exhaust odor.
Good luck,
Mark
Postmaster
Joined: Feb 2003
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Is this what your Holley carb looks like?
http://holley.com/HiOctn/ProdLine/Pr...C/f0-4160.html
Or this:
http://holley.com/HiOctn/ProdLine/Pr...C/f0-8007.html
The first one has a thermal choke that uses heat from the exhaust manifold to heat the coil spring in the choke housing. If you have the stock exhaust manifolds there should be a spot for a heat riser tube to connect to near the exhaust pipe.
The second picture has an electric choke. It also has a heat riser setup. The tube at the top of the carb sticking out at an angle over the choke housing is the air inlet. Air is supposed to be drawn in from the air cleaner, through the exhaust manifold heat exchanger and back up to the choke.
If your choke is not opening as the truck warms up then the spring is either broken or not heating up. If you cannot reconstruct the heat riser assembly you might want to consider either converting to an electric or manual choke.
http://holley.com/HiOctn/ProdLine/Pr...C/f0-4160.html
Or this:
http://holley.com/HiOctn/ProdLine/Pr...C/f0-8007.html
The first one has a thermal choke that uses heat from the exhaust manifold to heat the coil spring in the choke housing. If you have the stock exhaust manifolds there should be a spot for a heat riser tube to connect to near the exhaust pipe.
The second picture has an electric choke. It also has a heat riser setup. The tube at the top of the carb sticking out at an angle over the choke housing is the air inlet. Air is supposed to be drawn in from the air cleaner, through the exhaust manifold heat exchanger and back up to the choke.
If your choke is not opening as the truck warms up then the spring is either broken or not heating up. If you cannot reconstruct the heat riser assembly you might want to consider either converting to an electric or manual choke.
Laughing Gas
Joined: Jun 2003
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From: Chino, California
It sounds to me like you have not provided a way for the choke to react to engine temp. I am a strong believer in electric chokes.
The fact you have an open male fitting tells me you don't have any exhaust heat entering the choke bi-metal coil spring chamber. How do you expect the choke to open if you have not provided either engine heat or electrical heat to open it up?
That male opening you mentioned should have a metal tube and fitting hooked onto to it to bring exhaust heat from the manifold's crossover exhaust passage. Also, if that hole in the manifold isn't plugged, you will smell those terrible gases you describe. It's a potentially dangerous situation.
If it were mine, I'd plug the hole and go electric. It's the best way.
The fact you have an open male fitting tells me you don't have any exhaust heat entering the choke bi-metal coil spring chamber. How do you expect the choke to open if you have not provided either engine heat or electrical heat to open it up?
That male opening you mentioned should have a metal tube and fitting hooked onto to it to bring exhaust heat from the manifold's crossover exhaust passage. Also, if that hole in the manifold isn't plugged, you will smell those terrible gases you describe. It's a potentially dangerous situation.
If it were mine, I'd plug the hole and go electric. It's the best way.
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Senior User
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From: Colorado
The Holley looks like the top link you sent. The male fitting behind the choke is open. But, the choke only opens a 1/4 when the motor is fully warmed. I just bought the truck around 4 weeks ago and inside the cab is a metal tube that may go from the manifold to the carb. The spring in the choke is not broken, but was not hooked up inside the choke housing. You guys have helped alot. I'll go back to the truck and see what I can do, or maybe convert to electric. Thanks
Chris
Chris
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If the tube comes of the exhaust manifold or crossover it should be connected to the threaded fitting. They do have a tendency to rust out since they are carrying hot exhaust gasses. The end of the tube may have broken off.
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