Sometimes my car idles rough and a little high. Why does my carb (Autolite 2100) drop the engine RPM when I hit the top plate with the soft end of a screwdriver. Both the bowl, jets and needle/seat are clean. What gives? If it was trash in the carb, it seems I would find some, but everything always seems clean. Also, my car seems to be running rich at idle but doesn't like running smoothly if I try to lean it out (also drops my vacuum readings). Ideas?
How hard are you hitting it? Sounds like a vacuum leak because of a bad gasket. Also some ignition system hiccups if you can't lean it out. What is your ignition set-up?
sounds more likely related to the float levels being inconsistent.. and the tapping allowing it to move slightly to raise the level. or.. the fast idle rod(I think that's what they call it) is sticking and causing these fluctuations. as for the richness.. many possibilities there.. but I'd be getting timing close to right on the money before moving to fine tuning the fuel curve.
Timing set to 12° and I've got a Pertronix Ignitor III. When I hit it, I give it a decent pop....more along the lines of playing drums than driving a nail. For the float level, do you think I should raise or lower the current level to see if it will help? Also, my fast idle cam/arm broke and doesn't work, so if something related to it is sticking, I'm not sure what it would be.
Have you considered getting a new carb? If you were closer I'd give you the 2100 sitting in my toolbox.
Yeah, I'm considering a new(er) carb. Looked at some refurb 2100's, Holley 350cfm 2300 series, etc. I'm just not sure how bad mine is because everything seems clean and clear. One thing that does bother me is that I have to turn the idle mix screws out 4 to 4-1/2 turns to get max vacuum. It seems pretty far out. Any idea what it would cost for shipping for your 2100? What venturi size is yours? Mine's the 1.08 (287cfm). I'd like to at least stay the same size or go bigger.
I've got no clue what size mine is, I took it off my 74. I bought my car drove it for a couple days, noticed a really strong gas smell, found a puddle under the carb, decided I didn't feel like rebuilding it and bought a new holley. I don't think it would be too much to ship though, they weigh like 10 lbs wet and full of fuel. IF you're thinking of getting a new holley I'd say do that, I'm very happy with my holley factory re-man.
i just sent a carb to daniel (a looong way away).you can fit a one barrel for the six along with bubble wrap around it in a middle size ship anything that fits at the post office with $150.00 insurance on it for $18.with all the hoses and metal lines on it to. never did hear from daniel.
Maybe he's too busy driving with it? A new carb would be nice but it would be really good if I could just get what I have running right for now. I can't find anything wrong with mine but SOMETHING is not right and some signs point to the carb (rich gas smell, rough idle and rough up to 2000RPM, etc.).
Umm, man what carb am I using... this one. http://www.holley.com/0-7448.asp I love it. Bought mine from summit for less than that, but its the same carb.
That's exactly the one I've been looking into. I figure it would be a nice little bump in power without killing my MPG and me having to invest in a new intake.
If you want a carb to disapear, let the post office handle it. I had two Holley's go bye-bye via the USPS. I suspect it had something to do with their automated handling and bomb sniffers kicking it out from smelling the fuel fumes. UPS only for carbs.
The 500 cfm will give it a boost too, but with it's 50 cc accellerator pump, the mileage can suffer on some engines.(depends on the driver too) 4 bbl performance in a 2 bbl package. The 500 is half of a 750 double pumper 4 bbl.
When I put it on fresh I was getting 18 mpg daily around town, year later im around 15, but I just redid my exhaust and need to do new plugs and some more work on the distributor, maybe a new timing chain set. When I get my wideband afr installed and really get it tuned im hoping to get into 20mpg.
