Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem
Won't idle anymore.....and seems to flood?
fussfeld:
My setup, as of last Tuesday, won't idle anymore and seems to flood---because after it stalls it takes about 30-60 mins to be able to restart.
Granted, it had been sitting for a few months, BUT after i re-activated it this past Sunday and Monday, it ran well (by my standards at least---no stalling or flooding...)
The ONLY things i did Monday night, was 1) to get the secondary plates (not air flaps) to open more. This is a jeg's reman (i know, i know---didn't have time to do it right yet....) off of a truck casting. #17084349-ish. i can get the exact number if necessary.
When it was shipped, the secondaries really didn't open at all. i have now gotten them to open about 30-40 degrees.
2) And then did some "spirited testing" let's just say.
i did this secondary throttle adjustment Monday night. The problem didn't really start until Tuesday morning AFTER i did a full throttle test. Almost immediately after this first acceleration test, i could sense that the low speed and idling wasn't normal/not as smooth as normal.
The truck seems to run just fine (by my standards at least) above say 1200 rpms. It seems like it could do this all day. However, if i go to a stop sign etc. it will just stall out. Or if i stop and put it in neutral it will also stall out.
Since the problem happened just after a day of the carb functioning normally, i don't think the idle tubes could have gotten plugged so soon?
i am happy with the increased performance, but i'm not concerned about that anymore, because if i can't get the thing the idle, what's the point?
i will say that i got the engine to 3900 rpms, which i never did before getting the secondaries to open. i don't know if that has anything to do with the new problem? (Note: i have 2.56 rear diff)
-----choke does work fine.
----- fuel pressure last time i measured was about 5.5 lbs at idle and low speeds. Once i open the throttle, it would goes down to about 2.5-3.5 lbs. Electric pump.
----- Normal (for me) idle is 1000rpm neutral, 600 in gear. Won't do any of that anymore. If i put it in neutral and keep my foot on the pedal, it will stay running at 800+rpm all day. Once i let off, it putters out.
So, to sum: Engine will no longer idle and getting flooding. Ran good until immediately after adjusting the secondary throttle plates to open more and after doing acceleration tests.
fussfeld:
Cancel it:
The choke wasn't opening; The plastic plug that normally slides over the blade on the choke housing broke off and i was just using the metal clip portion----NOT the right way to do it.
i may have jarred it while adjusting the secondaries, OR it may have just moved under vibration. Whatever the case, it lost contact.
This little plug is something that is not really discussed much, but really shouldn't be overlooked.
i'll be ordering a proper plug tomorrow and doing it the right way.
fussfeld:
UNCANCEL IT:
Choke had nothing to do with it. It's still doing it.
Cliff Ruggles:
First thing to check is the secondary throttle plates to make sure they are full closed and sealing up the bores. Often when problems occur after going to WOT the huge plates are open some pulling in fuel off the rear nozzles flooding the engine.
Since it's a Jegs "remanufactured" carb difficult to help out.
I avoid anything commercially remanufactured like the plague. Have one on the bench right now sent here from a customer who bought one and it's JUNK. Main casting is leaking between the DCR passage and main fuel bowl so it drains the bowl into the engine after shut-down. He bought it for his big block Chevy pulling truck and just wanted me to check it out and tune it because it wouldn't work on the dyno. It's not going to work on anything and the best sound it will make this week is when I "tink" it off the dumpster outside the shop!.........Cliff
fussfeld:
The secondaries do close all the way and seal.
Just ordered an SR kit. i'd like to try that as a last effort. If that doesn't work, time for a new/different carb.
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