Hi everyone!
after scouring the threads I think I need to create another thread with issues about starting. I know sometimes more detail is better, so forgive if this gets too long.
Inherited a 1973 XJ6 from my deceased father. He did the swap. Few months ago, car would hesitate and lerch forward when I put the pedal down going up a small incline. This symptom got increasingly worse over a month or two. Until it finally was going so slow and lerching that it was parked. I replaced fuel filter. Still no help. When started, it would idle just fine. But same issues if driven. Called mobile mechanic. Mechanic says carb is bad.(Edlebrock 650cfm)
Then he says, might as well replace fuel pump too. Wants $800 for both, so had him do fuel pump first. ($150) After seeing receipts from car, they show dad installed carb in 2010. according to tuneups, oil changes, etc. car has only been driven 10k miles since 2010. Can a carb go bad in 10k miles??
Anything else this could be? Car will not start now, turns over fine, but even with starter fluid will burn fluid then die.

 

Depends how long the car sat with old gas in the carburetor. Gas turns into varnish and blocks critical, small orifices in the carburetor. So, yes, carb will go "bad". Not necessarily how many miles the car was driven but how long it sat w/o being driven.

 

When you press accelerator does gas squirt into carb?
Certainly sounds like the carb has a problem from what you are saying. Maybe the needle and seat are stuck closed. There arent too many moving parts inside a carb, if you feel confident enough i would try rebuilding it.
At a minimum i would try tapping where the fuel line goes in with the handle of a.screwxriver to see if float is stuck .

 

Didn't mean to quote your entire message, responded on my phone and must have hit wrong reply. Sorry

 

Thanks guys! The car never really sat, it was driven every week, just not alot. When it sat at my house waiting the mechanic it was 6 days. I will follow advise and add more comments.

 

Have you replaced the filter ? Maybe some fuel line blockage . Its one of those things where you have to be there to see / know what is going on.

If it will not start on its own (needs starter fuel) but does run when starter fuel is used, then its maybe a carb problem. Are you using an electric choke?
What type of carb?
What type of ignition system ?
Are all vacuum lines attached?
Do you gas fuel at the carb inlet?
Do you have strong gas fumes /smell when you are trying to start it? Flooding/
Have you removed a spark plug to see its condition?
Is all carb linkage intact and connected properly?

 

if you mash the gas while idling in neutral, will it rev? Can you hold it at 3500 -4000rpm without it dying? Is there enough gas in each tank? It's always either gas or spark and if it revs you've got good spark. Let us know.

 

Doesnt seem properly diagnosed. Throwing $$$ at the car and hoping for the best is not the best approach. A better approach is to spend 50$ on diag equipment. The mechanic should have these items already...if not...that's a red flag.

Have a look inside the distributor. Make sure your timing is set properly. Consider investing 9$ in a spark tester. After you get the car running on starting fluid then look at the fuel system.

If the carb is actually faulty...I'd get different carburetor. Consider a rebuilt Quarajet from Jegs. The Quarajet is possibly the best carburetor produced, ever! Small primary's for great throttle response and economy at part throttle and large Secondary's for all the flow you could ever need. You can buy them pre-tuned your your engine type. Fuel pumps rarely go bad and are easy to test with a glass mason jar. Just see if it fills. Wanna get fancy...go to your local big box auto parts store and get an in fuel pressure guage designed to be installed permanently. You could have 4 to 6 psi while cranking.

JEGS 4-bbl Remanufactured Quadrajet Carburetors | JEGS Performance Products


Ignition Tester at AutoZone.com - Best Ignition Tester Products for Cars, Trucks & SUVS

 

Agreed on the technical superiority of a Qjet over the Edelbrock, but it's probable that a new carb is not required at all. The existing unit can be fixed quickly and easily. Just sounds like dirty jets, stuck float at this point.

Probably the mobile mechanic wasn't even born when carbs were the norm and has no idea what to do.

 

Geno, icsamerica and Mikey, Thank you so much for the information. It is almost dark here so I will check the plugs and distributor tomorrow.

 

Had a similar problem while on holidays last year, didnt want to run much over 1800 rpm.
Ended up being crud blocking the mesh filter in the fuel bowl entry and some extra for good measure in the float chamber.

Changed filter (added another near the carb which is probably overkill) and a basic clean up got it back to normal

 

With all due respect to the mobile mechanic, and there is a lot, not their cup of tea to diagnose and fix "odd cars". They must do what is most likely work, quick and fast. defined as new parts. Quick success and no come backs is their motivation.


Some have the time to diagnose and rebuild a carb, fewer and fewer.
The mobile guy doesn't have the facility to clean it properly. Although, the old dunking can is probably gone by the way of "environmental safety".


1. Does the presumed SBC use the mechanical pump or the Jaguar
in the tank pumps? Not hard to test either for out put. Just hook up a line to the discharge side and run it to a container. Flow????


2. Look in the throat of the Edelbrock, hand pump the throttle linkage. If there is fuel in the bowl you should see two squirts. None ?


3. Not too challenging a task to remove the top of the carb and check the bowls. I suspect they are dry and contain a white powder. Tough to get it all out...


4. All SBC four barrel carbs are not interchangeable. Bore spacing differs...


5. Bad gas... Just did that exercise. I brought out my Honda powered SP lawn mower. Left it with a full tank at the end of last year. Rust resist. No Stabil additive though. I can usually get tit to burn "old" gas, but need ether to fire it. Not this year.... Dumped the gas. Siphoned off some from my Jaguar. Slick HF sourced transfer pump worked nicely. Filled up the mower, primed it with ether. Fired right
up and mowed the front "pasture".


As your car will fire on ether, it is a fueling issue....


Carl

 

Gorill,


In park, engine running, air cleaner off, rag in hand big enough to cover air horn, bring engine to 2500 RPM or so, holding throttle steady, smother carb till the engine nearly dies. repeat multiple times.
This often dislodges small particles causing idle or driveabiity issues.


Plan "B" find a diagnostician.


Can't count the number of old cars I fixed this way. Neighbor just cleared a Eldebrock that was only squirting out of one accelerator nozzle yesterday using this method.


Good luck.