DivinDriver

iTrader: (15)

And it's not in backwards, right? (just checking)

snwyvern

Well...
First: The FBVS came apart in four peices in my hand when I pulled it off the carb, I created a block-off and the symptoms didn't change.

Second: The top 'cover' came off the carbeurator five times today, each time the "hook" that holds the bits to the float wasn't in its' natural state of rest. Some clever off-the-car plumbing combined with a camera-scope-thing demonstrated that the needles weren't seating and are, in fact, being thrown (with some force) off of their little homes whenever pressure is applied.

... Which brings me to the unfortunate conclusion that perhaps a GP Sorensen rebuild kit was not the correct choice.

I'll be haunting the F/S section for a Carb/manifold and/or double checking the prices on a Sterling.

I appreciate all of your help. And yes, the fuel lines are right :P

DivinDriver

iTrader: (15)

That's odd, as Sorensen's are some of the better kits out there IMHE. It doesn't take a lot of pressure to unseat a needle - -that's why the stock fuel pressure is so low.

Have you ever verified your fuel pump output pressure? You might have one that's just running freakishly high for some reason.

You might also have saturated/leaky floats, that are not providing adequate force to close the needles. You can check them by floating them in a jar of gasoline, and observing how high they float. Helps more if you have a known good one to test against, though.

What's your exact year and build (12A/13B, manual/auto; fed/CA/CAN)? Might be I can scrounge you a useable FBVS from my jealously-covetted horde

snwyvern

Fuel pump checks out for flow and pressure. The floats floated (... lol) just fine, that was a test my 'helper' started with the first time the carb was apart.

... This somewhat reminds me of a 1911 I owned once upon a time. The slide would jamb indiscriminately. I swapped out individual parts; the ejector, the extractor all didn't make a difference. I finally disassembled the whole slide and purchased a new one. The slide off of my original 1911 went onto a friend's Imbel frame and never had a problem EVER...

Perhaps there are manufacturing errors in the needle/seat assemblies that are not... 'easy to detect'? I'm sticking by my orig. solution, and just replace/upgrade the carb.

(79 SA post 50000 chassis)

Jeezus

iTrader: (4)

Sticky needle. Same thing happened to me, I replaced the whole carb top with a spare carb top and it ran fine.

Also, replace your return line. I cleaned out the carb and after about 30 feet the carb would be gunked back up. Turns out the inside of the return line was rotted and it dumped crap into the floats. Stick a Q-Tip in it and see if it gathers trash.

DivinDriver

iTrader: (15)

I'd bet on it... as the resolution that finally got rid of my post-rebuild flood was to swap the needles into the opposite seats, which if any effect at all should have made matters worse. Instead, my seating failure went away.

Does yours have the vacuum power valve actuators in it? (long spring-loaded rods extending down from the lid past the floats?)

If yes, I've got a nice, clean, padded trashcan here I'd let you gently toss the old one into, if you're really ready to give up on it...

snwyvern

All of the soft fuel lines on the vehicle have been replaced.


If I don't find a "cheap" intake/carb combo in the FS area in the next couple of weeks, I'm going to order one from Sterling... I'll be using mine as a core (Used parts place has a couple of unrebuilt carbs floating around too, but I really, really, really don't want to rebuild them before putting them on my car (for obvious reasons) I may try and do some horse trading with Ster. to provide him with some quality builders in add. to my own faily carb)

snwyvern

I'm going to give it *ONE MORE TRY*-- I came into posession of a bucket full of "carb bits." I'm going to painstakingly re-disassemble the entire taco and put it back together again. The needles are going to get swapped out side to side unless I can find other parts that are compatible. I've already budgeted $300 to replace the damn thing, so I may as well give it the ol' in-out, in-out one more time.

snwyvern

As an update to anyone else who may have had similar issues--

The plumbing on the fuel tank side was incorrect; fuel was entering the carb through a pressurized tank and the incorrect spigot on the tank being used.

snwyvern

I figure I better update this thread since I "solved" the problem.

Improper plumbing at the fuel tank AND the check&cut valve was filled with spider egg-sacs. (No kidding...) I took it apart and cleaned it and now *that* problem is gone. (Fuel was coming IN through the return.) Car ran OK-ish after that, the timing would wander by 5-10 degrees and I would have random power-stealing gremlins. I removed the rat's nest, FBVS, anti-afterburn vac. pot and... something else. Now the car idles like hammered dog-crap and I have no power after 4k.

Yay. Carbeurators.

Kentetsu

Throw a Sterling on there (if you can find/obtain one) and live happily ever after.









.

snwyvern

I've put together a new ignition system (replacing points dizzy with a 82+, TFIDFIS, new wires, etc.) In the next few days I'm going to toss that in there to lock the problem(s) down to just the carb. From what I can tell there are three on-the-car adjustments, the idle mixture, idle speed and the... vertical screw near the OMP linkage that seems to hold open the butterflies.

I'll see what's what and do a fuel pressure/volume test just in case.

If that doesn't work, I'm going to pick up a square-bore intake and do an Office Space fax machine destruction routine on the stock carbeurator.

... Damn it's good to be a gangsta'.

IanS

iTrader: (4)

I rebuilt my carb one time. Then also I rebuilt my Sterling (bought it used). You know how I fixed my sticky needle problem (I know this wasnt exactly your problem)? I put back in the old needles with the new seats and BAM! Good stuff.

Oneiros

I agree with this as well, I've rebuild 10+ carbs with the GP sorenson kits and experienced many problems with their needles and seats. I don't use the hooks that hold the needles on the float tab any more, as they would get jammed all the time and cause flooding. So that would be my advice - remove them.

You may have to re-adjust the float tabs so that they dont allow the needles to slip too far from perpendicular, or easier is just raise the float drop a little (around the 50-52mm mark).

eViLjAy

+1 on tossing in the original needles and seats. New ones always give me headaches. also if fuel was going in through your return line than possibly the one way valve is on backwards. you should be able to disconnect the return from the carb and blow into it and hear bubbles at the tank. should have been impossible for fuel to come out of that line. A faulty or backwards one way could result in inconsistent fuel pressure causing what you are describing. Happened to me.