Carburetor: High/Raised RPM Idle Issue "Out of the Blue"??? - Explained & Repaired

[@jayr1757]

This was useful information. I don't know if my distributor is set up the same, but it's always good to understand mechanical engineering. Thanks

[@redneckwithajeep5001]

My 66 Belair is doing this. I didn’t think of the 8 miles of linkage going to the carburetor

[@HammerHeadGarage]

the problem with the sandpaper or screwdriver fix is that it takes off the glaze thats purposefully put on those contacts. The parts will wear rapidly from here on.

[@maxwelltheobald4470]

my '85 country squire ran so poorly until I discovered the problem was the specs of the smog cam. It was so frustrating trying to tune it. so, I'm just finishing an RV cam install (and 1g to 3g alternator conversion so I can go to an electric rad fan). let's hope I start to see some of the benefits of the headers, exhaust, intake, 4 barrel, and FULL MSD ignition system I already installed! I learned a lot from your channel. thanks.

[@RetiredTony]

Good old Carbs...miss working on them. it was always something haha

[@ThunderHead289]

I usually don't have too much of an issue, though with the rotstang Iv fixed a lot of stuff outside of the engine .....

[@alan6832]

@@ThunderHead289 it ran better broken than fixed! faster with the same amount of fuel, so why not advance your idle timing, turn down the idle speed screw, and save gas at idle? of course you might need to do this without advancing your timing while cranking or accelerating.

[@ThunderHead289]

alan6832 it didn’t actually - the ideal amount of initial timing is that which doesn’t show vacuum on the ported port, yet still has transfer slot exposure!

[@alan6832]

@@ThunderHead289 The ideal amount of initial timing is that which uses the least fuel per minute without stalling or damaging the engine. transfer slot exposure is not a function.

[@alan6832]

@@ThunderHead289 so you fixed it right in the field, except for one big spring is lopsided, so 2 springs with half the pull each would balance better, at least at idle.

[@Rezection]

Awesome video. Always enjoy your methods of aproaching, explaining and repairing automotive issues. Keep those videos coming. Are there any videos coming with the galaxie? Miss that car. Cheers mate.

[@ThunderHead289]

I hope so. Believe me, I miss it as well. The black one and the red one.

[@damiancaldera7684]

dude. great video. Thank you

[@jordanparker8359]

Good video man! Having this issue and I often overlook the simple stuff

[@anontimothy8]

Little package of nylon caps is $6-7 at O'Reilly's now, at least in Washington (where everything is designed to scam your money away)

[@thetruth8958]

I have a question for you My car shuts off when I hit the brakes to come to stop any idea why ?? c30 1984 Chevy 3 speed manual 6 cylinders in line

[@joelg.8517]

What if my idle comes down slowly and I have already checked for vacuum leaks and there are none?

[@HypealotNetwork]

did you find out the issue? i have this now

[@fklr-369]

Old school cars have individual souls you have to talk to that precious piece of machinery ask her what's wrong land truly listen and she will tell you the problem and so much more. My 1985 mustang GT 5.0 4barrel carb all original! I love my mature milf

[@geholzman]

Secondary not closing fully after opening(hot-doggin') is common also , makes blower motors surge at idle , also...

[@nummerfinfeable]

hey there Thunderhead289 where did you get the dizzy cap protective gaiter/boot from, off roads shop maybe???

[@jocrp6]

I've seen bent piston's knock those springs off like that,,, specially on Fords,,

[@rustybritches6747]

"BENT PISTONS"?????? LOL 😂

[@glennmanchester5696]

I think he meant the piston return springs

[@coyoteserranoband]

Are both jets supposed to work at the same time? For a 2 bbl? Or is one a idle jet and the other a main jet.

[@josephfriedrich9792]

I know this video is old, but what would cause like a white slime/foam to spray out of the squirter nozzle

[@mr.iowegian]

Hey Luke, I have a question. Have a 66 Mustang with C-Code 289 with a mild rebuild. I have a mild cam, performer intake with Edelbrock 600 4 bbl with E-choke. Dudes at shop tuned it and it runs great. They removed the vac advance and plugged the vac chamber on the distro. Like I said, runs great but it idles a bit high for me. It is an auto -- what do you recommend for idle speed in Drive? What about in Park? Here's what I have now: Cold/sorta warm, she idles at about 650 in park. When I drive a while and it gets to full operating temp, it idles in Drive about 650 and in Park about 950. Reasonable? I would like it to be a tad lower but then it prob won't idle for 15 minutes until she gets hot. Anyway, would appreciate your opinion of idle speeds. Also what's up with the plugged vac advance? Thanks bud!

[@itsallaboutgamez8884]

I HAVE CIVIC 1995 CARBORATOR ENGINE IS FANTASTIC IN DRIVING AND ALL THINGS ARE WELL BUT WHEN I COME FROM A SMALL TRIP AND IT'S USUAL THAT ENGINE GETS BIT WARM. WHEN I TURN THE IGNITION OFF THE CAR TAKES A BIT JERKS. I HAVE NO PROBLEM WHAT SO EVER DRIVING BUT STILL I GET OUT OF CAR ON IDLE IT'S STILL U KNOW DURING SHUTTING MAKES WEIRD JERKING SOUND. (IF U HAVE ANY SOLUTION THEN TELL )

[@steveballard1463]

Good info , Thanks for sharing

[@jamesdesjarlais1641]

I’ve got a 1984 Pontiac Parisienne, I can’t get my carb to idle down without Revving my engine near red line. Before I would just tap the gas and it would idle down, but now that doesn’t work. Once it idles down it runs normal though

[@abrahamaguilar2008]

Same issue here... any advice?

[@ernestobambeno3137]

It’s 45 degrees outside rn and my carb is slightly close and it won’t start but yesterday it was running fine

[@jasont.1530]

Im having fuel come out of the manifold vacuum port after I pull my vacuum gauge off. Any thoughts? Maybe a bad booster leaking fuel?

[@saldav420]

I have a bronco with a 351 Windsor Holley 4bl that was recently rebuilt, I brought it in for a bad misfire. Turns out it was the distributor. Well now at a stop when it’s idling It tends to surge/lope if that makes sense like it’s going shut off, it never did that before so I’m wondering if you had any advice. Thank you🙏🏽

[@ThunderHead289]

If it's carburated, it could be a lot of things - nothing necessarily broken or wrong as much as I'd say tuned poorly. Especially if a shop did the work, mechanics today are parts changers at best. I have a lot of tuning videos on my channel, if I had to guess it's just that.

[@yeeyeebmx9322]

Love your vids keep up the good work and possibly more motorized bike videos?

[@ThunderHead289]

I have actually been working on mine. Sat for two years with gas in it. Fail. There are 3 more vids I'd like to make.

[@yeeyeebmx9322]

ThunderHead289 ok looking forward to some great vids!

[@forestlawrencegrading9154]

that's only the second time in my life I've ever seen a distributor do something like that the one in my grocery getter truck the weight spring and everything came off of one side the pin broke off flush

[@kevinhagberg1648]

Hey I need some help! Im in the process of getting my grandpa's 66 mustang back on the road. Its got a 289 w/ 4bbl Carb. I just had the carb rebuilt (the car ran but poorly) Got the carb back on with new hoses and lines. Car starts up and runs a lot stronger but won't stay running now. Runs solid for 30 seconds and seems to idle down and die. I drove it just before pulling the carb, so I know it should run and drive. Any suggestions? I really know very little about carburetors.

[@ThunderHead289]

There's probably nothing wrong with the engine or carb - you are going to have to take a step back and learn about carb tuning.

[@joebiscit]

Mine starts up and sits in idle just fine. But then I drove around the neighborhood and stopped and it was alright. But as soon as I put it in park it shot up to 2,000 rpms

[@01groundzero]

Mines do the opposite.. Idles fine but after I drive for a while and then it starts idling too Low around 400-500 rpm as if it wants to stall. It did stall one time but fired right back up

[@CCAutoWorks]

What do you think would make an Edelbrock break up for a sec after ever gear manual transmission but first is fine

[@jdubski5690]

Mine runs good throttling, but then idles down and dies. Won’t stay idling

[@AudiolibrosLecturasNocturnas]

Found the solución?

[@maddmaxx636]

Could this cause a distributor to act weird in terms of the timing bouncing around and being at one setting and then not being able to start and then being WAY TOO advanced? Since my motor/distributor seems to having (What Im dubbing) timing walk. Where I set it to something and then either after a shutdown and startup the timing has changed or when trying to change the timing it walks all over the place. Like Its at 18 degs and when retarding it goes into the ATDC. NOTE: Nothing regarding of the carb has been changed. No idle/ported vacuum or high idle.

[@714xoc5]

Hey man quick question so I have Holley 4160 carb is causing back fire and shit it even started a fire on the carb luckily I was to put the fire out be for anything else happened so my question to you what can cause that to happen carb wise I know the car is timed right cause recently saw one of your videos on how to find tdc. Also prior to this happening the vehicle was running somewhat properly it would sputter though upon acceleration the vehicle is 84 fox body if you have any tips would appreciate it and thanks for your time.

[@speakfreeley4473]

In my case right now it's low RPMing. Any tips for that?

[@abenezerlegesse-ti3sd]

Hey i have corola 2000 and carbrator this on it has cruk and it don't bring fuel kukle

[@Midnight_Hemi]

So my moter ran ok then I took my carb off and rebuild it and now it idels at 3000 rpm and replaced file filter it's has a brand new full pump that is made for the moter the pcv is good and the grommet was just replaced I don't understand what's going on.

[@jonhsmith2706]

Did you ever figure it out?

[@Globeglider]

Hi ThunderHead, I've been using your excellent videos for Holley trouble shooting. I've put a brand new double pumper on my old 351 Cleveland and I just can't get it to idle. But I found creating a big vacuum leak it would idle ok. (I pulled off the rocker cover PCV hose.) Seal the vacuum and it cuts out again. Ever experienced this?

[@arthurmoore1524]

Ever find a fix? Is it a PCV conspiracy? Are they putting something in the gas and oil to finally activate the seed they planted with the pcv valve in the 60s? Are the old steeds trying to warn us of whats to come? I'm having a similar problem with a 010 350 but only occasionally.

[@Globeglider]

@@arthurmoore1524 lol no ,I gave up on carbys, i did an engine swap and now have fuel injection. I put in a mighty Australian ford Barra. Though I expect the carby issue was internal seals leaking and over-fueling.

[@user-fl1jv9cv7z]

You videos are always good! but I have question of you don't mind. I have a 4160 I rebuilt to specs. tried everything and my secondaries won't open up. I tried running compressed air across the port with the throttle open and they don't open up. Engine was off. Everything else checks out what do you think it could be my carburetor guru friend

[@user-fl1jv9cv7z]

never mind I fixed it with an Edelbrock

[@chevyinthecutz9055]

My choke on my carburetor won’t kick down so u know why?

[@holymiumtv7560]

I got a bit of an issue with a 65 mustang. It's got the 289 with the motorcraft 2100 carb. you have to set the idle super high to keep it from stalling in drive. idles decent in drive but in park neutral it sounds like it's running 1800+ rpm. smoked the intake to check for any vacuum leaks which none were found. checked the vacuum modulator on the trans and it's not leaking. timing is set to 8 btdc. vacuum advance appears to be working. I also notice I only have about 15 inch of vacuum at idle and about 10 in drive. adjusting the idle mixture screws does not change vacuum at all. is there something inside the carb that could fail and cause these issues?

[@holymiumtv7560]

ThunderHead289 ThunderHead289 yes it's got quite a bit coming out of the breather. vacuum advance is plumbed to a port on the passenger side of the carb. timing was set with a timing light with vacuum advance disabled.

[@ThunderHead289]

+Holymium TV make sure that it is hooked to manifold vacuum ie when you pull the tube off, it should create a vacuum leak. What rpm was your timing set at? If you can, idle it back down to 800 or so rpm in park and set your timing to ten degrees. We still have more things to work through, but we need this for a baseline

[@holymiumtv7560]

ThunderHead289 I have no tach to go off but when I was setting the timing I brought the idle speed down to what I believe sounded somewhere around 700-900 rpm. vacuum advance supply line shows 15 inch vacuum off that port off the carb. I have the the front cover and pan off at the moment (fixing oil leak, coolant leak, and changing the chain due to about 12 degrees of chain slack.) will redo timing like you said when I get it back together and let you know where we are at. chain set should be here tomorrow or friday.

[@ThunderHead289]

+Holymium TV sounds like you are on the up n up on this stuff thus far. When you do the timing chain, snag yourself a true roller. They have double roller links and don't slack out. Once you get it back together, check back here with me when moving forward if you would like further help!

[@holymiumtv7560]

ThunderHead289 sounds good. thanks.

[@larryneyii2162]

great video!!! wish I had your videos when I was young !!!! I'm old ha ha ha

[@ThunderHead289]

For sure, me too. That's why as I go along I try to make them for others !!!

[@hectorortega9131]

mr. Thunder, in this particular motor of yours, whats the difference0 when you run your carb spacer and with out the spacer??

[@ThunderHead289]

The spacer itself works as an insulator and keeps the temps off the carb. A 4 hole unit increases low end torque and air velocity and signal through the boosters while an open spacer expands the plenum and adds to top end power.

[@jamesmoats1926]

I want to put a carb on a 96 302 roller do I have change anything in motor

[@ThunderHead289]

you will have to change several things over to convert to carb - _ obviously a carb and a 4 barrel intake - id recommend the performer 289 edelbrock intake and the summit 600 carb - a different distributor that has mechanical timing advance and an oldschool style ignition coil - injection to carb bypass style regulator - aeromotive makes one of these units ____ and of course if it is an auto, that year will be an electronic auto, so you would have to go with a ratchet shifter and manual valve body.

[@rubenleavell]

Could a poor battery and bad charge cause rough idle?

[@billyschannel997]

It should only affect your start up, or if you stop at a light and the car dies. Check your spark plugs

[@terminashunator]

HeyI was curious, do you ever plan on repairing rust damage in the future? Or are you gonna just run it till it start dragging stuff on the ground? :) What are your plans for this car?

[@ThunderHead289]

It's beyond saving unfortunately. It's a salvage title car from a rear end collision - the body is buckled in the rear and puckered out on the sides. All that aside, the rust is too significant underneath. I'm going to run it till the engine keels over or the body buckles. And with the 4.56 ...., it won't be long.

[@terminashunator]

I love your videos, watched the whole Rotstang series.. I forgot that it was crumpled like a tin can. Best of luck to you!

[@ThunderHead289]

+James Pourroy hey thanks! Friday it rolls out for power tour. There is an autocross event in Newton Iowa. I plan to run the car as hard as possible during that - so it might be on its last few rides this week.

[@AX3L87]

How would you go about converting a vacuum carb to non vacuum carb?

[@ThunderHead289]

Vacuum secondary? If you have a holley you can simply switch the rear float bowl and metering block yo the same as the front unit. - add the levers and you are good to go. If you are a madman, you can put a sheet metal screw in the throttle linkage to manually open the secondary

[@AX3L87]

I'm sorry, I meant to say how do I convert a vacuum carbureted engine to a non vacuum carbureted engine and what kind of gains will I get from doing so?

[@EASTCOASTIMPERIAL]

Hi,quick question. How would you set your idle on carbd 89 foxbody? Car was EFI.

[@ThunderHead289]

What do you mean “how would I set my idle” ? As far as what screw? What rpm? Is it an auto or manual car?

[@EASTCOASTIMPERIAL]

ThunderHead289 thanks for responding. It’s a five speed. I want the rpm to drop to 900 instead of 1,000.

[@ThunderHead289]

IMPERIAL SEMI KING gotcha, okay - there should be a curb idle screw that adjust the throttle position on the driver side of the carb. Turn that counterclockwise a quarter of a turn. You should be good to go then. If you want to really hone it in, you will want to also adjust your mix screws with a vacuum gauge. Search adjust mix screws with a vacuum gauge. You will find my video

[@EASTCOASTIMPERIAL]

ThunderHead289 really appreciate the help. Thanks.

[@EASTCOASTIMPERIAL]

ThunderHead289 one more question. Lol. What should the idle be on a SBF that’s carbed? I know EFI is 950.

[@theinvestorsmind2547]

My mustang seems to skip or misfire when I am in neutral or park and I steadily rev it past 2500 or 3k rpm. Any idea on what that could be?

[@ThunderHead289]

Could be a few things here though the first thing I'd look at is the ignition timing. What do you have your initial timing set to?

[@panaoutsios1990]

900 rpm for all the cars is best for driving in town

[@ThunderHead289]

Panayiotis Toumazou did junkyard digs tell you to say this? 😂

[@panaoutsios1990]

@@ThunderHead289 is smother

[@tanitadames8375]

I have a 78 malibu 2bbl with 305 engine. Just put a brand new carb on it and it idles like this any help?

[@flickina5114]

You sound like hank hill

[@didiask592]

My car idling low it’s a like 800 to 600

[@forestlawrencegrading9154]

so has Brian Collins been stealing some of your videos he copped a bunch of them from Jonathan w

[@ThunderHead289]

I can't find this Brian Collins guy, can you give me the title of one of his vids?

[@forestlawrencegrading9154]

ThunderHead289 1962 Dodge D100 first start in 25 years he stole it from Jonathan w and one of Jonathan w subscribers commented he seen one of your videos on this guy's page Jonathan W has the links on his I'm not good with that stuff

[@ThunderHead289]

i cant find him anywhere - i wonder if he somehow blocked me

[@retrochristmas7329]

How much cocaine do you recommend doing before doing this repair?

[@teegearhead512]

I guess he was trying to race a Chevy. Hahaha! ;)

[@ThunderHead289]

+Troy Gearhead haha! You never know!

[@hanamanthah2652]

Ft

[@dudemanguyfella3736]

Thanks for the info!