Carburetor Question
Thread Starter
Instructor
Joined: Nov 2005
Posts: 238
Likes: 1
From: Oklahoma City Oklahoma
Carburetor Question
I have a 1980 L48 all original car except the carburetor. The car starts and runs fine, but if I'm at a stop and floor it, it's very sluggish with hesitation and takes a few seconds before really engaging and taking off. What is that from? Is it the carburetor or something else.
I had to replace the carburetor last summer with a rebuilt chevy one from a carburetor shop (it was only $129).
If I am already going 25+ or faster and floor it, it takes off like a jet, so it only happens when I am at a stop.
I had to replace the carburetor last summer with a rebuilt chevy one from a carburetor shop (it was only $129).
If I am already going 25+ or faster and floor it, it takes off like a jet, so it only happens when I am at a stop.
Safety Car
Joined: Nov 2006
Posts: 4,449
Likes: 0
it could be from 3 things, one: the carb is running rich, two: the carb is running lean, or three: your timing is off
Id start with the carb
Mine does the EXACT same thing and Ill be tuning my carb here in the next week or so
Miles
Id start with the carb
Mine does the EXACT same thing and Ill be tuning my carb here in the next week or so
Miles
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
It could be several things, but here are the first two I would check:
First, with the air cleaner off and the engine NOT running, look down the barrels of the carb and pull the throttle linkage. You should see two strong squirts of fuel in the primary bores. If not, or if the streams are weak, your accelerator pump plunger needs to be replaced.
If that is good, the next most likely problem is the secondary air valve adjustment (the air valve is the butterfly on top of the secondaries). On the passenger side at the end of the air valve shaft, there is a flat head adjustment screw. You may have to move the green linkage rod to see it. It is horizontal. You must loosen an allen screw that points up from underneath it first (holding the adjustment screw in place as you loosen the allen screw), then adjust the screw to add tension to the air valve opening, then re-tighten the allen screw. There is a set number of turns these are supposed to be set at, but I don't remember it off the top of my head. But that is just the starting point. Here is how you set it optimally, just using where it is as a starting point:
Since you have a bog, you will want to tighten the adjustment. Go about a quarter turn at a time from where it is. Try it out after each time you tighten it (If it does not straighten out after the first couple of adjustments, you may have some other problem). Once the bog goes away, try loosening it 1/8 turn and see if it is still good. The idea is to have the valve as loose as possible without causing any hesitation.
God bless, Sensei
First, with the air cleaner off and the engine NOT running, look down the barrels of the carb and pull the throttle linkage. You should see two strong squirts of fuel in the primary bores. If not, or if the streams are weak, your accelerator pump plunger needs to be replaced.
If that is good, the next most likely problem is the secondary air valve adjustment (the air valve is the butterfly on top of the secondaries). On the passenger side at the end of the air valve shaft, there is a flat head adjustment screw. You may have to move the green linkage rod to see it. It is horizontal. You must loosen an allen screw that points up from underneath it first (holding the adjustment screw in place as you loosen the allen screw), then adjust the screw to add tension to the air valve opening, then re-tighten the allen screw. There is a set number of turns these are supposed to be set at, but I don't remember it off the top of my head. But that is just the starting point. Here is how you set it optimally, just using where it is as a starting point:
Since you have a bog, you will want to tighten the adjustment. Go about a quarter turn at a time from where it is. Try it out after each time you tighten it (If it does not straighten out after the first couple of adjustments, you may have some other problem). Once the bog goes away, try loosening it 1/8 turn and see if it is still good. The idea is to have the valve as loose as possible without causing any hesitation.
God bless, Sensei
Pro
Joined: Oct 2007
Posts: 549
Likes: 5
From: punta gorda florida
It could be several things, but here are the first two I would check:
First, with the air cleaner off and the engine NOT running, look down the barrels of the carb and pull the throttle linkage. You should see two strong squirts of fuel in the primary bores. If not, or if the streams are weak, your accelerator pump plunger needs to be replaced.
If that is good, the next most likely problem is the secondary air valve adjustment (the air valve is the butterfly on top of the secondaries). On the passenger side at the end of the air valve shaft, there is a flat head adjustment screw. You may have to move the green linkage rod to see it. It is horizontal. You must loosen an allen screw that points up from underneath it first (holding the adjustment screw in place as you loosen the allen screw), then adjust the screw to add tension to the air valve opening, then re-tighten the allen screw. There is a set number of turns these are supposed to be set at, but I don't remember it off the top of my head. But that is just the starting point. Here is how you set it optimally, just using where it is as a starting point:
Since you have a bog, you will want to tighten the adjustment. Go about a quarter turn at a time from where it is. Try it out after each time you tighten it (If it does not straighten out after the first couple of adjustments, you may have some other problem). Once the bog goes away, try loosening it 1/8 turn and see if it is still good. The idea is to have the valve as loose as possible without causing any hesitation.
God bless, Sensei
First, with the air cleaner off and the engine NOT running, look down the barrels of the carb and pull the throttle linkage. You should see two strong squirts of fuel in the primary bores. If not, or if the streams are weak, your accelerator pump plunger needs to be replaced.
If that is good, the next most likely problem is the secondary air valve adjustment (the air valve is the butterfly on top of the secondaries). On the passenger side at the end of the air valve shaft, there is a flat head adjustment screw. You may have to move the green linkage rod to see it. It is horizontal. You must loosen an allen screw that points up from underneath it first (holding the adjustment screw in place as you loosen the allen screw), then adjust the screw to add tension to the air valve opening, then re-tighten the allen screw. There is a set number of turns these are supposed to be set at, but I don't remember it off the top of my head. But that is just the starting point. Here is how you set it optimally, just using where it is as a starting point:
Since you have a bog, you will want to tighten the adjustment. Go about a quarter turn at a time from where it is. Try it out after each time you tighten it (If it does not straighten out after the first couple of adjustments, you may have some other problem). Once the bog goes away, try loosening it 1/8 turn and see if it is still good. The idea is to have the valve as loose as possible without causing any hesitation.
God bless, Sensei
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
If that is good, the next most likely problem is the secondary air valve adjustment (the air valve is the butterfly on top of the secondaries). On the passenger side at the end of the air valve shaft, there is a flat head adjustment screw. You may have to move the green linkage rod to see it. It is horizontal. You must loosen an allen screw that points up from underneath it first (holding the adjustment screw in place as you loosen the allen screw), then adjust the screw to add tension to the air valve opening, then re-tighten the allen screw. There is a set number of turns these are supposed to be set at, but I don't remember it off the top of my head. But that is just the starting point. Here is how you set it optimally, just using where it is as a starting point:
Since you have a bog, you will want to tighten the adjustment. Go about a quarter turn at a time from where it is. Try it out after each time you tighten it (If it does not straighten out after the first couple of adjustments, you may have some other problem). Once the bog goes away, try loosening it 1/8 turn and see if it is still good. The idea is to have the valve as loose as possible without causing any hesitation.
God bless, Sensei
Since you have a bog, you will want to tighten the adjustment. Go about a quarter turn at a time from where it is. Try it out after each time you tighten it (If it does not straighten out after the first couple of adjustments, you may have some other problem). Once the bog goes away, try loosening it 1/8 turn and see if it is still good. The idea is to have the valve as loose as possible without causing any hesitation.
God bless, Sensei
