Carb acting up.

Thanks mark! I learned learned something new.

 

Me too! The outside of my fuel pump is as new. Carb was rebuilt less than a year ago. No problems at all till now.

 

Since you smell raw fuel on the plugs, and it is not idling smooth, I think, if it is carb related, you have fuel leaking through the bottom of the bowl, and/or needle seat is not sealing. The newer fuel has been a mess on the older carburetors and it has been hard to find good materials. But they are out there now.

 

Carb was rebuilt using the newer type materials to deal with ethanol and such. Other than what has happened recently she was working fine. When first rebuilt I had a similar issue but then sent the carb back at which time the jets and "idle circuit"?? were redone as well and the carb was allegedly bench tested on a non stock motor similar to mine. When it was shipped back and installed all was well. Something has happened between then and now (right after the Gumout and gas) which really wasn't that long a period of time.

 

Update:
I finally ran the car below a quarter tank today and got a fresh tank of gas. I purchased 91 octane and even added LUCAS octane booster. Amazingly the car actually ran worse at idle. When I got home I sprayed a whole can of Gumout down the carbs throat at high idle, cleaned the PCV valve up and guess what, the idle actually got better. Somehow, some way, I disturbed and/or sucked up something. I’m going to run the car hard with what’s in the tank now and see what happens. Could the sock in my gas tank have disintegrated and is causing my issues? I have never had my gas tank cleaned out and I am wondering is using a cleaner disturbed something. Boy is this frustrating!

Merry Christmas and Happy New Year everyone!

 

As few guys have said, the needle and seat obstruction sounds like a probable culprit since it clears itself then acts up again, have u checked the fuel filter? Is the spring behind the filter? You'll need to pull the carb and clean the bowl and jets out, sprayin cleaner on ,thru and around the carb isnt doing anything, also a second inline filter is always a good and simple addition, as well as servicing the fuel tank, its alwags something simple

 

I recently went thru this and ended up REPLACING the pcv valve instead of cleaning it. It made a huge difference. Here's why :
If the PCV system is not functioning properly, the flow of crankcase vapor into the intake manifold will not be properly metered. This, in turn, will upset the fuel/air mixture for combustion and can cause rough idling or even stalling of the engine. Furthermore, intake and exhaust valves, in addition to spark plugs, may eventually be burned and rendered useless, prematurely affecting performance and requiring expensive repairs. To assure trouble-free performance of the PCV system and, in turn, the engine and vehicle, routine maintenance of the PCV system is absolutely recommended and required.
[h=2]Myth Time![/h] Millions of owners think that if a PCV valve rattles when shaken that it is okay. Wrong!
Just because it rattles doesn't mean its calibrated spring is metering correctly. Cleaning the PCV doesn't accomplish any thing either. A PCV valve should never be cleaned and placed back into service. Cleaning a PCV valve will result in a clean PCV valve; not a new PCV valve.
There are contaminants that will remain in the PCV valve that can never be flushed out. Additionally, there is an amount of wear that will be experienced by the spring that cleaning cannot replace. Good Luck

 

Thanks for all the help and advice guys!

I already have an additional inline filter along the frame rail. Its not that old but I am considering changing it, checking the one in the carb and replacing the PCV valve which also is not that old. If the problem persists Ill consider pulling the carb off and having the tank cleaned internally as it has never been done. Is it possible for the sock in the tank to disintegrate over time and clog things up?

Merry Christmas and Happy New to everyone!

 

I myself have never seen a sock get to point of falling apart, get gummed up and somewhat clogged on the other hand yes kinda common, pull the filter out of the carb cut it open and pull the paper apart that will tell you whats in your tank and lines, spray ether around the intake to head, fittings, carb base, throttle arm etc change in idle speed if sprayed in certain spot then youve found part or maybe all the prob, this may have been mentioned b4 tho also make sure idle speed screw is in contact with the arm or and the spring is pulling the arm closed or against the screw stop completely, some times depending on cam and carb mods and idle mixture settings along with timing the carb doesn't require any turns on the speed screw, altho in a mild setup as yours id imagine you will need just a couple turns on the screw idle is intended to set with timing and the mixture screws the speed screw is there just for the last little fine adjustments

 

PCV valve question.

For my 350 with a 284 cam, TA manifold and 4bbl are the PCV part numbers AC/Delco CV679C or Purolator PV679 (currently in the car) correct ?

 

Your tank sock question, I have seen many that just fall apart with a touch. I take them off for that reason, and have good filters before the fuel pump and after.