Holley Carburetor - Cold Start Fast Idle Adjustment
HTML-код
- Опубликовано: 5 июл 2024
- Does your car carbureted car have trouble idling on cold mornings? Hidden on the passenger side of most four barrel carburetors is a second idle adjustment called the fast idle. This is located behind the electric choke on Holley carburetors and is only accessible if you manually open the throttle. The fast idle screw adjusts your idle RPM when the car is cold and the choke is activated which can prevent the car from stalling. This is different from the curb idle screw which adjusts the idle when the car when the choke is off. Ideally, the fast idle should be set to about 1200 RPM to allow the car to warm up and go into gear without stalling on a cold morning. The carburetor in this video is a Holley 80457 and is 600 CFM. This is a 1986 Chevy C10 with air ride suspension.
Наука
Doing the Lord’s work! I needed to know where the curb idle was and this is just what I needed! Camaro is back up and running right now.
A small ignition wrench can also be used on the fast idle screw if it's difficult to access with a screwdriver.
Great simple precise video. Thank you
Nice dude, just done mine on my 79 c10 shortbed great vid kool truck 👊
1/4 SAE wrench works too, my 670 street avengers screw is always exposed (kind of) so I don't need to hit the throttle to make the screw visible.
Good tip, thanks
Great, thanks pal !!!
No problem 👍
The red plastic cam on my holley 670 gets stuck in the top part. Has to be pushed down manually
im havikg a diffirent rno sound issue. it sound like a very high pitch tone and regardless of whixh way i adjust the screws. i can tell a different spund comes int play while adjusting the screws and it occurs right on cold start . i had also boticed one of thr air hoses gad came off by mistake but im not feelimg air suction or air going out so im guessing its clogged. any wild guesses or suggestions?
I own a 84 f-150 with a 4 barrel 4180c carb . I set up the choke perfect for cold start , don't see no binding issues etc . The cold engine fires up good but once warmed up , there is no way that the choke will kick off the last step on the fast idle cam , no matter how much I back off the fast idle screw ??
The only way is for the choke to come off the last step on the fast idle cam , is by pushing the cam lever manually . Then having to adjust the choke thermostat for a warm engine . All is good until the engine cools off & now the choke plate is open too much .
I was wondering if it could be a possible bad choke spring ?
Ì GOT the same problem Did you fix that cam stucked in the top position
Is there a certain number of RPMs the fast idle screw will drop or increase based on a 1/4 turn of the screw? Not sure how far to turn it..
It really depends on the engine, carb size and temperature. I would adjust it about a quarter turn at a time until you are happy with it.
I have three old carburetor trucks that run like crap when they're cold. While I think I probably have some vaccum issues, all three will start up fairly easily. Two have rebuilt carburetors on them but all three act the same.
They typically start up pretty much immediately but then start skipping & smoking badly. I can't tell if the smoke is rich or lean on any of them but they tend to smooth out, for the most part, once they start getting warmed up.
They're 1979 2.3L Ford, 1982 1.9L Mazda & 1983 2.4L Nissan engines.
Do you have any suggestions, based on this limited information, 😁 as to what might be going on with them? I'm in the humid southeastern United States.
Thanks!
🇺🇸
If they are smoking, they are probably running rich. If the choke is staying on too long, it would cause that. On most carburetors with an electric choke you can loosen the circular cap and turn it counter clockwise to reduce the time that the choke is on. It could also be a bad needle/seat on your float bowl which would cause it to dump fuel into the engine rather than seal off once the float bowl fills with gas. This is pretty common actually. Those little rubber seats get old and won't seal anymore. That might also explain why the start good, then run bad once started.
I think I'm having similar issues on a mobile home. the rpm sounds very high and won't summer down anything I do to the screws and the tone sounds very high pitched as if it's a clogged vacume issue.
if I play with the carb screws than I cam hear a second rpk as the idle raised, startles or lowers if I domt cut it off and also if I dotn male it hard to restart.
smoke sesms to also be a bit black in idle I'm able to simmer it down based on standard idle sounds but the Hugh pitch rpm sound doesn't sound like the roms ot would have in idle or even when reving a motor if you catch me any
78 Doddge 440 b300 Sportscoach Mobile Home.
Got my electric choke dialed just right, but I had no high idle with choke on. I adjusted my high idle screw and bam sounds just right on a cold start, but it will not kick down and return to normal idle when I blip the throttle. Any suggestions??
Havin the same problems
Same issue.you fixed it?
What rpm you running on drive? 550 or 600?
I've since sold this truck. If I recall it was in the 700-750 range.
600 to 750 rpm in drive with foot on the break
how are you supposed to adjust this without dumping a ton of fuel into the engine?
open the throttle. ONCE. Hold it open, make your fast idle adjustment and then let go. Yes the accelerator pump will give a squirt, but its not sustained. It wont just keep dumping gas in, your fuel pump isn't running, and a carb draws fuel via vacuum. Your key should be off, engine not running. Therefore no fuel pump running, no vacuum, no flooding of the engine. . .unless you keep pumping the gas and flood it with the accelerator pump. But like I said, don't do that.
My issue is that the throttle blip will NOT make it come down to curb idle setting, i'm super stumped
Loosen the hi idle screw tension a tad, this loosens the spring which will allow you to kick off the hi idle after shes warm
I’ve always had this issue with the factory settings. I’ve never had a new carb that I didn’t have to back the fast idle screw way out on because for me they are set to idle at like 3k rpm when I get them out of the box
@@abeneufeld9690by “loosen high isle screw tension” are you referring to backing the screw out?
Where's you fan shroud?
Not all cars are equipped with them
Would you happen to know wrench size?
I don't off hand. If it does have a hex head it is probably in the 1/4 to 5/16 range. I don't recall if mine had a hex or not.