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Carburetor tips and tricks thread.

10K views 27 replies 8 participants last post by  boothboy 
#1 ·
I am a bodyman, not a mechanic, let's get that straight. My brother is a mechanic and I have never had to learn a thing about the motor because he was always there to do that for me. I did his body work and paint, he did my motor stuff. But he is now over 100 miles away from me so I have learned a lot. Besides driving fuel injected late model cars for the last number of years, and me not knowing much to begin with I have been stuck. My Rambler has been running kinda funky and not knowing where to start but the basics I gave him a call to try to cut thru the crap.
It was "bucking" for lack of a better term. It ran great, started, idled, revved up good, if I drove it hard it worked fine. But if I was just cruising shifting thru with a light throttle it would buck terribly like the ignition was breaking down or it was running real lean.

It sounded like a dirty needle and seat or water or junk in the float bowl to him. He told me to clamp off the fuel hose and run the carb dry, start it back up and the fuel rushing in will often clean stuff out. And, or, remove the air cleaner and run the motor up to a high idle and then put a rag over the carb down tight choking it off of air until it almost dies, then remove the rag and get it running smooth again, and again raise the idle up and do it again. What this is doing is sucking junk out of the bowl, clearing the bowl out of everything.

I did this and WHAM problem gone, that easy, five minutes tops and problem gone. It's the type of thing he would have done for me and I didn't even know what he did, or if it was in front of my I would just forget because I didn't need to remember it.

What tips and tricks do you guys have that we can learn from?

Brian
 
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#5 ·
I talked to him on the phone earlier and he confirmed yes it could only be a bandaid. Sometimes the junk gets sucked out other times I just knocks it loose and it stays in the bowl waiting to be caught again later. We will see, I'm going to give it a go. The cool thing is it gives you plenty of warning so you can limp home to fix it. :D

Brian
 
#6 ·
Using a rag to choke the engine down like you described will sometimes remove junk that's plugging the air bleeds. If that's the case, the "fix" is permanent, but could be pointing to unfiltered air somehow reaching the carb, or a dirty filter (I know that's not your particular problem).

I would follow this up by using carb cleaner spray to get rid of the rest of the deposits inside the carb air horn/throttle bore- if there are any. This can sometimes dirty up the plugs, but a light cleaning will take care of that if need be.
 
#8 ·
When I work on carbs I get a long bolt and chuck it in my vise and mount one corner of the carb to the bolt. One nut and washer under and a wingnut on top holds the carb nicely and allows it to swivel if needed. A pic for you.
In this pic I used a valve cover tall hold down bolt.
 

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#10 ·
You know BB I have been doing that for years on just about anything I work on. I learned it on wheels and just kept doing it on everything. But it is not something everyone does so very good tip.
I just put my Thermoquad together last night for the Gran Sport and carefully did just that.

Brian
 
#15 ·
Actually I've rebuilt a lot of carburetors using a single bolt in a vice to support it with no problems. What ever it would take to brake off a lug from the base would probably do more damage to the rest of the carb in the process of braking off the lug. I went and bought a adjustable carb stand for rebuilds mainly because when I used the one bolt vice method what ever I dropped disappeared some place on the floor or under a bench or wherever. Using a stand on top of a clean shop rag is a much better solution. Things don't bounce as much on a soft surface.

BB :thumbup:
 

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#19 ·
This is one that helped me last night when I put the carb on the Buick and fired it up. One day back awhile I was firing up the car for the first time after it had sat for years and right as I was cranking it an old friend came walking into my garage. This guy is a motor guy thru and thru and the first thing he asked as he stopped me from cranking was "Did you fill the carb with gas?" HUH? How do you fill the carb I asked and he showed me how you pour gas into the bowl thru the vent. Sure enough, it fired right up and kept running.

I did the same thing last night, it fired right up and ran.

Brian
 
#23 ·
Randy was right, it was just a bandaid this time, so I pulled the carb and opened it up and cleaned it out, I also added a fuel filter, I didn't have one!

It runs like a champ now. :D

Brian
 
#24 ·
Every time I have the carb off I adjust the idle screw, getting those little
slots in the bore just right.
But when I adjust the carb on the car that setting gets invariably lost.
So today I took the carb off sat it on the stand and set the idle screw to just touching, like this.


Then I counted the turns to get the slots right, on this carb it was just half a turn, waaaaay off what I actually thought it was.
You might have to figure in the return spring tension when the carb is back on the motor, quarter turn I reckon.
In my case it did´nt need it.
Now if I lose my adjustment with the carb on the motor I can reset to just touching and add my half turn.
 
#25 ·
That is exactly what my brother showed me when I took the carb off the Gran Sport, count the turns on all the adjustments and record them so you can start where you were, you knew it was running, and adjust from there for the fine tune.

Brian
 
#26 ·
Generally when setting up pretty much any carb, whether it's on your car or lawn mower you can pre set your idle mixture screws to 1-1 1/2 turns and the same with your idle speed adjusting screw. That usually will allow you to start your engine . Then after warm up you can fine tune it with your tachometer. That being said there is nothing wrong with counting turns from original settings.

BB :thumbup:
 
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