BRAD ARTHUR
i stll have a backfire-stall on a quick take off with a cold motor. once its warm no problems. its sounds like its backfires through the carb. its a pain when you pull out on the highway and accept to take off and it backfires you let off and gradually accelerate, so it wont stall out and dies.
i don't think its a vaccum leak checked all above intake, even plugged the pcv and held my hand over the breather seemed to be no vaccum leaks under the intake.
the timing is set at 10*btdc about 18* cent. and 10-12*vaccum. and i 've changed it all over and changed the adv. springs now the lightest springs possible for early timing advance. i rarely see over 4000-4500 rpms.
and the jets/rods and springs i have went way rich to way lean and doesnt seem to matter much , but i think it stems from the carb
my accelerator pump is in the hole closest to the pivot and i run that bigger nozzle . my thought was the stumble ,hesitation , backfire was from off idle to power mode. thats why i tried the biggest nozzle #46.
but yesterday i was mess again, had the air filter off and started it to see something? it never would do any backfiring at a stand still only when you first take of. but yesterday it bakefired in the shop at stand still with filter off it was at the secondaries - this was after a bunch off carb cleaner though. but i think my secondaries may have not been closing all the way. so i bent the linkage on the right side of carb.
the backfire stayed lit until i shut it down and blew it out, so it may have been the carb cleaner.
i stll kept gassing it immiediately off idle and finally a few times backfired through the primaries, almost seemed as burnt carbon came from the throat. no flame color i could see.
after all this went for a quick drive and didn't feel backfire but it was warmed up, but there is a hesitation when dumping the clutch and mashing on the accel. and if you keep it mashed it will bog out and die.
jeepsr4ever
edel-1406 600cfm carb?
dimension4
Brad and I have a similar problem. We both have 600 cfm edelbrock on 304's. I have a torker II manifold, I think he told me he's got a performer. I have a backfire at idle on the even bank. Cyl #8 plug is really black, the rest just look a little rich because I stepped the metering up one position. After 2500 I have a lot of power, but I can't tell if it's still misfiring. We've tried lots and lots of stuff but no luck yet.
BRAD ARTHUR
is this common with this carb?
today i read more on timing and backfiring and carb hesitation , but no exact problem found. i went a checked and changed timing again
now @ 10* initial idle
25-26*@1500 rpm
30* @ 2000 rpm
34-36*@3000rpm
10* vac adv hooked to ported vaccum
i changed the adv. springs in the distributor mr. gasket part #929 for hei's
1 light &1med. spring.
it idle cold 700rpm's and 750 warm
ran on a cold day 48* outside and it only reached 160* water temp. it has a 180* thermostat ran 12 miles. it still has a backfire , but runs smoother with more power.
i also am running the #1456 rod(.073x.047) with pink step up spring w/ 2.5 out @idle mixture screws
when i was reading the timing at one point the reading was very erratic and nothing had changes was still running smooth @2500rpm's. i found the timing light wire was touching some other wires other than the #1 wire. and yes some of my wires are close and touching, but the wires only have 3000 miles on them . could this cause the backfire?
dimension4
What is your manifold vacuum reading again? Have you eliminated the problem?
David
73hornut
Maybe bad compression in one cylinder?
Goose
This may sound kinda way out there.. But I found it by accident..I had a similar problem, when you gas on it backfires through the carb.. it was carbon tracking inside the distributor cap. See the posts are pretty close together on the amc, and you can get condensation as the air in the cap heats up on warm up. I changed cap and rotor. (even though mine looked to be in fine shape there was small lines of something between two of the posts.) problem solved..It's a cheap thing to try.
dimension4
I just put in a new dizzy. HOLY CRAP!!! Now it runs almost perfectly, just gotta get the metering set now.
Lifted79CJ7
Goose
Heh heh sometimes its the wierdest things..
dimension4
Yeah it's always the only part left that you haven't rebuilt or replaced. So here's how to fix a jeep:
get a list of all the parts in the car (long)
start replacing.
when you have just 1 part left to replace, then you know what is wrong.
