So when turning in air/idle in lean , when she starts to rise highest rpm point your saying to turn back rich by 3/4 to 1 full turn back ,? I was taught to bring to highest idle then back of 1/4 turn at best thanks j
I got a built 355 with big cam and holly highrise intake and 600cfm 4 barrel carburetor, it has hesitation on quick acceleration and sometimes makes a loud pop out of the carburetor, once it gets on the top end it has good response and pulls good but its having a hard time getting up and going. I feel like the motor can make alot more power but have no idea what to do, should i toss the 600cfm and get a 750cfm?
@@ermiliodagoat7492 I figured out the problem, the timing wasn't advancing quick enough with the set up Im running it was sucking to much fuel and air and not enough timing and it needed a bigger accelerator pump nozzle it wasnt getting nearly enough gas, I went from a 32 to a 40 and now the truck does no back firing at all and runs like a champ
@@ermiliodagoat7492 putting lighter springs in the msd distributor to advance the timing quicker was a big help but it still was wanting to pop sometimes right off the launch, so we ordered a size 40 accelerator pump discharge nozzle and now the truck absolutely rips
@@ermiliodagoat7492 and another thing it was running way to rich so I turned the idle mixture screws all the way in till the motor stalled and backed them out a half a turn, that brought out a lot of power, I got a couple videos on my channel they don't really show much but it shows how the truck ran before and how it runs now, it needed 3 things 1. Faster timing 2. Bigger accelerator nozzle 3. Idle mixture screws needed adjusted
While idling and car in park, carb works fine As soon as I put in reverse or drive to move the car, engine just shuts off You think maybe is vacuum leak or still some adjustments need done on the carb
What is your transmission? On autos with AT, there’s a kickdown function that I’m not very familiar with, but it sounds like that needs adjusted. It’s an armature b/w the throttle cable hook-up and the carb body. You will need to do some digging into how that works. My understanding is that the AT when taken out of park will lower the idle, and it seems it is too far for you. Also, when setting idle, engine needs to be at operating temperature, back the idle screw all the way out -> set your air screws 1.5 out -> if it will not idle, turn the idle screw in a half turn at a time until it will run, then adjust an air screw like he said, but ensure that once you adjust one side, you set the other side to be the same. Then use idle screw to get idle where you want it, then make another pass on the air screws using your setting that you ended on as the new baseline (not the original 1.5).
Great explanation. I have a Carter AFB On a small block Chevy engine. Two Issues that I cannot seem to fix. #1, It is very difficult to start after setting for 24 to 36 hours or longer. The 2nd and much more serious issue is the terrible gas mileage, aprox 5 MPG. I suspect it's running extremely rich. I know how to adjust the idol, But is there a way to adjusted the "rich/lean" at higher RPMs.
Use a msd ignition box for better start and fuel economy. Also New battery..new air filter..new spark plugs.Smaller jets for primary jets. Bigger acceleration pumps..
When this happened to me, I found that I had one of the springs on the throttle linkage holding the throttle open slightly. I had attached it to the wrong hole.
Does it run rough before it dies? In other words, does it appear to be struggling to run or is it running pretty smooth when it dies? If it’s running rough, it’s most likely ignition or fuel related. Let the exhaust manifolds cool, then start the engine. Have someone keep the engine running and immediately touch the bottom of the manifolds close to the exhaust port of the heads (or use a laser thermometer). Once they start getting warm, quickly check all 8 exhaust ports. If any port isn’t warming up, I’d suspect a bad spark plug or bad spark plug wire on that cylinder. While it’s running, take the plastic end of a screwdriver (or plastic mallet) and tap on the float adjustment screws (the hex heads on the top front and top rear of the carburetor….if it doesn’t have them, tap on the little circle areas where the fuel line enters the bowl). If a piece of trash in the fuel line gets stuck in the needle/seat it will cause a problem and tapping the screw will sometimes free the trash and fix the problem. Also check the timing advance. If those check out OK, could be bad gas or carburetor needing adjustment or rebuild. If it’s running smooth but dies, it’s most likely curb idle adjustment or incorrect timing advance.
@@TyTanium1294 yes it does run rough before it dies. Shakes a little then the Rpms drop and eventually dies out. I noticed it bogs down when I turn the ac on as well.
@@calebmiears5866 this guy gives a summary of the Holley carb adjustments. czcams.com/video/bv9NIIJ3rFc/video.html I’d say watch this video and then check the adjustments on your carb.
Thank you sir!
thx so much... so how do you adjust the other screw?
And the air screw adjustment ?
2 barrel carburetor holly running Rich
So when turning in air/idle in lean , when she starts to rise highest rpm point your saying to turn back rich by 3/4 to 1 full turn back ,? I was taught to bring to highest idle then back of 1/4 turn at best thanks j
rich carby makes a strong smell or gas like its very fume but no smoke? my holley qft defiantly needs help
Lean conditions with burn holes in exhaust valves
On 350 engine my car
Valve covers the passenger side is getting alot hotter than drivers side car runs smooth not runing hot
I got a built 355 with big cam and holly highrise intake and 600cfm 4 barrel carburetor, it has hesitation on quick acceleration and sometimes makes a loud pop out of the carburetor, once it gets on the top end it has good response and pulls good but its having a hard time getting up and going. I feel like the motor can make alot more power but have no idea what to do, should i toss the 600cfm and get a 750cfm?
Same problem with mine
@@ermiliodagoat7492 I figured out the problem, the timing wasn't advancing quick enough with the set up Im running it was sucking to much fuel and air and not enough timing and it needed a bigger accelerator pump nozzle it wasnt getting nearly enough gas, I went from a 32 to a 40 and now the truck does no back firing at all and runs like a champ
@@ermiliodagoat7492 putting lighter springs in the msd distributor to advance the timing quicker was a big help but it still was wanting to pop sometimes right off the launch, so we ordered a size 40 accelerator pump discharge nozzle and now the truck absolutely rips
@@ermiliodagoat7492 and another thing it was running way to rich so I turned the idle mixture screws all the way in till the motor stalled and backed them out a half a turn, that brought out a lot of power, I got a couple videos on my channel they don't really show much but it shows how the truck ran before and how it runs now, it needed 3 things 1. Faster timing 2. Bigger accelerator nozzle 3. Idle mixture screws needed adjusted
While idling and car in park, carb works fine
As soon as I put in reverse or drive to move the car, engine just shuts off
You think maybe is vacuum leak or still some adjustments need done on the carb
I have same question, can anyone reply please
What is your transmission? On autos with AT, there’s a kickdown function that I’m not very familiar with, but it sounds like that needs adjusted. It’s an armature b/w the throttle cable hook-up and the carb body. You will need to do some digging into how that works. My understanding is that the AT when taken out of park will lower the idle, and it seems it is too far for you.
Also, when setting idle, engine needs to be at operating temperature, back the idle screw all the way out -> set your air screws 1.5 out -> if it will not idle, turn the idle screw in a half turn at a time until it will run, then adjust an air screw like he said, but ensure that once you adjust one side, you set the other side to be the same. Then use idle screw to get idle where you want it, then make another pass on the air screws using your setting that you ended on as the new baseline (not the original 1.5).
Is this the same for the 2 barrel Holley carburetor too?
yes it is
Great explanation. I have a Carter AFB On a small block Chevy engine. Two Issues that I cannot seem to fix. #1, It is very difficult to start after setting for 24 to 36 hours or longer. The 2nd and much more serious issue is the terrible gas mileage, aprox 5 MPG. I suspect it's running extremely rich. I know how to adjust the idol, But is there a way to adjusted the "rich/lean" at higher RPMs.
Use a msd ignition box for better start and fuel economy. Also New battery..new air filter..new spark plugs.Smaller jets for primary jets. Bigger acceleration pumps..
Accelerator pump for starting, the main jet, and or cam for milage?
I have an old pontiac with a holly that probably needs rebuild . I put msd with e3 plugs and she fires right up.
what if there's NO change when you mess with the idle adjust screw?
When this happened to me, I found that I had one of the springs on the throttle linkage holding the throttle open slightly. I had attached it to the wrong hole.
What if it won’t idle or dies when I try to idle
Does it run rough before it dies? In other words, does it appear to be struggling to run or is it running pretty smooth when it dies?
If it’s running rough, it’s most likely ignition or fuel related.
Let the exhaust manifolds cool, then start the engine. Have someone keep the engine running and immediately touch the bottom of the manifolds close to the exhaust port of the heads (or use a laser thermometer). Once they start getting warm, quickly check all 8 exhaust ports. If any port isn’t warming up, I’d suspect a bad spark plug or bad spark plug wire on that cylinder. While it’s running, take the plastic end of a screwdriver (or plastic mallet) and tap on the float adjustment screws (the hex heads on the top front and top rear of the carburetor….if it doesn’t have them, tap on the little circle areas where the fuel line enters the bowl). If a piece of trash in the fuel line gets stuck in the needle/seat it will cause a problem and tapping the screw will sometimes free the trash and fix the problem. Also check the timing advance.
If those check out OK, could be bad gas or carburetor needing adjustment or rebuild.
If it’s running smooth but dies, it’s most likely curb idle adjustment or incorrect timing advance.
@@TyTanium1294 yes it does run rough before it dies. Shakes a little then the Rpms drop and eventually dies out. I noticed it bogs down when I turn the ac on as well.
@@calebmiears5866 this guy gives a summary of the Holley carb adjustments. czcams.com/video/bv9NIIJ3rFc/video.html
I’d say watch this video and then check the adjustments on your carb.
My 85 bronco will idle in every gear but drive. I have to feather the gas for it to stay on at stop lights.
WHAT CANT U JUST SAY RICH IS LEFT OR RIGHT
Omg... EXACTLY WHAT I NEEDED TOO
Confirming that turning air screw CCW is making it richer (higher amount of fuel in the fuel:air).
Also, @DTruth, love your pic. Praise Jesus!