Holley 1920 need help

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Carlb87

Carlb87

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Well I have a 74 duster with a 225 in it with a 1920 carb. It doesnt like to stay running at idle unless you have it running pretty high rpm. I was woundering if the choke was supposed to open completly vertical because if I slightly choke it the rpm rise and it smooths out. Then I can drop the idle down to a good speed. So to me it sounds like either my choke is opening up to far or im not getting enough fuel. It has a new pump on it and the filter looks new. So what does that leave? Reabuild? If so where is the best place to get a good quality rebuild kit?
 
Carlb87 said:
Well I have a 74 duster with a 225 in it with a 1920 carb. It doesnt like to stay running at idle unless you have it running pretty high rpm. I was woundering if the choke was supposed to open completly vertical because if I slightly choke it the rpm rise and it smooths out. Then I can drop the idle down to a good speed. So to me it sounds like either my choke is opening up to far or im not getting enough fuel. It has a new pump on it and the filter looks new. So what does that leave? Reabuild? If so where is the best place to get a good quality rebuild kit?
Click to expand...

I am new to Mopars. I did Beetles and Chevys for 30 years...However....
Rule of thumb.
Check for a Vac leak, spray some carb cleaner around it, throttle shaft etc...See if the rpm's jump up while doing that.
Also, my choke is slightly tilted closed, but not much.
I rebuilt a crap ton of carbs, but sent mine to a local Holley guy to get done.
It's probably not hard to do. But after I got mine back, it idles at 650rpm in gear, and very smooth. It was worth it.
 
slant 101...

grab the carb and see if its loose... i dont know why but the carbs on slants always loosen and will make a bad leak.

do you know how to set timing? if yes go to 10* adv with vacuum adv unplugged. speaking of did you check the diaphram? suck on the hose and see if it holds vac or not. also bypass the OSAC valve on the passenger side firewall.

for starters set the idle mixture on 2 turns out.

also check brake booster for leak.

also run the valves to .010 int and .020 exh
 
You need a vacuum gauge. Harbor freight sells a cheap one that'll do you just fine.

You want to be hitting at least 17hg on the gauge...20hg is ideal. Anything below 17 and you'll start having idle problems.

To find vacuum leaks, spray carb cleaner around the base of the carb and where the intake runners meet the head. Anywhere where air can escape. If the engine idles faster when you spray carb in a certain spot, you know it's sucking air through there and you'll need to fix it.
 
some times if you take the idle mixture screw out. and blow air in that hole with a air nozzle, it will blow dirt out of the idle circuit. and might run better. it doesnt seam to hurt any thing, cause the air stays in the idle circuit.
 
Yes, the choke should be fully open once warm. Your slightly closing it, and noticing a smoother idle, is the classic test for "running too lean". I had the same problems for many years in my 69 Dart 225 w/ Holley 1920. I changed intakes, head jobs, searched for vacuum leaks w/ propane, bought rebuilt carbs. When it persisted after a new long block, I bought another 1920 and it then ran unbelievably smooth. I think there are many bad rebuilt carbs, and many here concur. The 1920 has a sealed metering block, so it is easy to have unseen clogs in the fuel passages. One guy here posted that he blows air thru the passages in reverse flow to clear the idle passages.
 
805moparkid said:
slant 101...

grab the carb and see if its loose... i dont know why but the carbs on slants always loosen and will make a bad leak.
Click to expand...
No way! In the 4 or so years I've been here and ss.org, I've never anybody say that! When dad bought my dart back in 2003 he discovered the carb was so loose it would tilt back on the intake on hills!!! We always thought it was the po's son (who also cranked the torsion bars way down to the point that we had wheel rubbing issues.)

BillGrissom said:
I think there are many bad rebuilt carbs.
Click to expand...
Yes! Any parts store rebuilt unit is JUNK. You can buy the kit and rebuild it yourself but don't buy rebuilt units. If anybody needs good rebuilt cars, contact SlantSixDan cause I believe he still has a huge stash somewhere.
 
Thanks guys. I forgot to get a vacuum gauge but tried the carb cleaner method and couldnt find a leak. Check the mounting bolts and they were good. I set the timming, blew out the idle mixture passage and readjusted and still no luck. Ill have to pick up a vac guage and check that if not Ill get that carb kit on the way and hopefully that will fix it. Oh and i forgot to mention it runs fine while your driving but when you come to a stop it dies unless you keep on the pedal. Weather it is in neutral or the clutch is depressed doesnt make a difference.
 
starting in 1968 ALL engines was fitted with a lean idle circuit. the holley 1920 was one . the idle circuit can be fixed. BUT is VERY hard to do. my friend had one on 1969 dodge van. it would not idle. long story short. i fixed the idle jet. when done it would run so good we got it to idle at 250 rpm, so smooth you could count the fan blades.
 
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