We have a 1986 E250 Fiesta High-top Class B RV... 5.8L... 4bbl... C6 Automatic... 124,000 original miles.

The original carb has now been rebuilt [at least twice, by two different outfits]. The shop cannot get this thing to run worth a tinker's damn.

Something bizarre we have missed? It definitely is a fuel pickup/ delivery issue. Shop recommends getting a new carb, not wanting to invest/ waste more dollars & time on it...

Find another - original - rebuilt?
> Anything to be aware of before spending coin on such?

Or, locate an aftermarket - new - carburetor?

Mandatory; Electric Choke / EGR intact.

Edelbrock, based in Torrance, CA, does not offer any C.A.R.B. compliant carburetors... a "visual check" [which is mandatory] at any smog test center will fail their equipment.

Any suggestions would be greatly appreciated!

 

Do you still have the identification tag from your original carburetor and can you post a picture of it (the tag)?

 

If it's fuel delivery, have you checked your fuel pressure out of the pump? Carburetors aren't foolproof, but having it rebuilt twice and still not running correctly would indicate to me that I should be looking elsewhere for problems. It could still be a bad carburetor, but first I'd check the fuel pressure and fuel delivery to the carb, then just for giggles, I'd check the spark and make sure that it's good and strong.

 

A] I'm sure the ID Tag is there... would have to visit the shop, and take a pic... Monday...

B] I would hope that the mechanic [all kinds of certifications/ years in business] would have checked the fuel pump...

Then again, sometimes these problems are right in front of us.


After sitting for several years [simply non-use], I got it back running...
Ran like a turd...
Felt like gas was not reaching carb when foot was applied to pedal, or it would get gas sporadically...
Takes awhile for any decent idling...
As long as you don't need to stop it seems to run alright...
Bogging down @ stops, but not stalling...


New:
Carb [rebuilt] - once again, this past week, after being rebuilt 3 years prior [then parked w/ no use]
Plugs
Plug Wires
Rear Fuel Tank Sender
Alternator [upgraded "1-Wire"]
Fresh Gas
Fresh Oil

Mechanic initially found a vacuum leak underneath the carb...
Put back together, and it still wasn't right...
Rebuilt the carb...
Mechanic just does not like how it is running...
He is preferring to go w/ a replacement carb, thinking we are wasting time & money.

However it would appear that only rebuilt Ford carbs are legal for use in CA.

 

Checked today... of course, the tag is missing.

Did verify that it is a 4180 Holley for Motorcraft - as stamped on back of carb... as well, it looks like I posted this in the wrong forum - should be in the later years Small Blocks, sorry.

 

IMHo, it sounds like it is a very basic type problem.......could be typically fuel pressure, fuel pump (including a pinhole in the pump diaphragm which symptoms are slight miss at high rpms and progressively gets worse...but the idle is fine) to carb adjustment to poor quality parts used in the rebuild (kits are notorious for this) ....... to mechanics who really do not understand carbs....have to tried...

Culver Carburetor Company
4921 Marine Ave
Lawndale, CA 90260
(310) 679-1616

they do not use "kits' but create their own ........ they will also trouble shoot which sounds like what you need.

 

Beechkid,

Yes, it does sound like something very basic...

Met/ spoke today w/ the mechanic, who described the issue more succinctly;

@ Low Idle = runs rough/ stumbles.

Adjusting to a higher idle eliminates this issue, BUT leaves the engine idling far too high.

Where is the happy medium?

The mechanic has plenty of carbureted vehicles on site... I do believe he is very capable. However, it is likely we are missing something far too simple/ obvious...

Thanks for your input!

- Wm.

 

I do not have the specific specs for that year of engine....but in general, the 351 V8's (ie 5.8 ltr) idle speed is typically 625 rpm, with the tranny in drive.....this can vary on a stock engine to as low as about 550 rpm and as high as 700 rpm.

Your mechanic might also check to ensure when the carb was rebuilt, they didn't replace it with a non-feedback carb.

but, IMHO, there is something else going on including the possibility of improper ignition timing settings, internal carb gasket leaking, etc.