So, in my continuing fuel starvation saga (another thread), I'm almost ready to rebuild the webers. Rode her hard again yesterday, and she ran pretty nicely for awhile and eventually started to starve very hard at really hard throttle. Took a very good look in the tank, and the walls look pristine, but in the circular baffle area where the sock is, there were many very tiny pieces of black crud, and the sock, though very hard to see well, looked pretty dark too.

Opinions?

Also, I'm thinking that since my fuel filter was pretty clean, that the sock might be my real problem...should take care of that before making the carbs clean and possibly getting more crap in them.

If I do pull the tank and replace the sock, shouldn't I replace the fuel line back to the engine? Any threads on that? Can I just hook a new line up to the old and pull it through?

Thanks in advance,
Ken

I'm trying to help you here but you haven't answered this question from your other thread. There seems to be a few threads of yours on this same issue. It would be a bummer if you go through the work of changing the sock and that wasn't your issue. Starvation usually happens after a hard acceleration in one of the higher gears. In another thread you said it happens more often in first gear which has me wondering if it truely is a fuel starvation issue. It would help if you explained what happens.

Either way if your sock is clobbered change it. You can even remove and clean it if it's in one piece.

Don't bother cleaning the sock. If you go through the trouble of removing it, just replace it. They're something like $7. And IIRC, there is a crush washer built into the end of the sock.

Find a radiator shop that will clean and seal your tank, and change the strainer sock at that time. I would probably replace all the rubber fuel lines regardless, and put in a new fuel filter too, after you have the tank cleaned.

No you can't just pull new lines through. There are plastic lines in the tunnel and the flex lines connect to them. There's enough evidence to support a bias against keeping the stock plastic lines, particularly if the visible portion of your plastic lines are at all brittle.

Chris Foley - CFR a banner advertiser on this site, makes an excellent set of stainless fuel lines that will last longer than you. If you have carbs, and never ever plan to go back to FI, or never ever plan to run a return fuel line (not needed for street car), you can use just a single fuel line.

Sorry...didn't see the other post you made on that thread. It sounds exactly like what you're describing in your second paragraph...I get the pops and snaps and then it starts to completely die until I let off. On the way home from CT. it did completely die, and I had to wait 10 minutes to restart it. Then it was "OK" as long as I just maintained a steady pedal and no hills showed up to tax it or cause me to give it more gas.

Let me go pull an ET and get back to you...thanks a million.

Does the condition of my fuel tank sound good, bad...? Like I said, the tank looks nice and shiny, but the area surrounding the sock looks a little dirty and the sock looks dark.

Sounds like your on the right track. If the tank is shiney I wouldn't mess with it. Replace the sock and wipe out the gunk around it. I would change the fuel lines myself. It's cheap insurance. Are you going to upgrade that fuel pump? If the sock replacement doesn't fix it thats what I'd change next provided your carbs are set up correctly.

Main= 115
AC Jet = 200
ET = F11

Looked at all pieces with a jeweler's loop and they look spotless.

I have to believe the carbs are set up correctly as it was "built" in 1989, not a new build. The car was brought out of storage by a team of Porsche techs who have been rebuilding and fixing Porsches for almost 40 years. It ran great until I filled it up a few hundred miles after leaving CT on my way back to MD. That's when the trouble started. It was either bad gas or the fresh fuel (vs. old fuel with StaBil in it) loosened up enough crap to clog the sock, or carb or fuel pump. The filter element had about 5-10% of it covered with microscopic black crud, but was (of course) 90-95% clear. I figure it;s most likely the sock or the carbs, So far, the emulsion tube with main and AC jets looks clean as does the idle jet I pulled. Since the filter was relatively clean, I'm thinking (and I'm far from an expert here), that the crud is in the sock.

Main jet seems small to me. I'd run a 1.25.

Educate me on that. It's a 1.7 with a 1911 big bore kit. I'm assuming the jetting was done back in 1989 when all the work was done. Even if a 1.25 would be an improvement, it certainly isn't my current problem, is it?

I had a fuel starvation problem. Finally looked inside my tank and found the problem. I would pull the tank and have it boiled and sealed. it solved my problem anyway. If your tank has never been pulled and the lines replaced it would be time well spent anyway. Good luck

What did your tank look like? Like I said...mine looks beautiful other than some micro flakes around the base near the sock and the sock looks "dark" and collapsed to me.

Having mains that are too small will cause those same symptoms. You can verify that by idling your engine for a few minutes and then rev the engine up close to redline and hold it there for a few seconds. Try it unloaded and loaded. If you get a lean pop you can be pretty sure your not getting enough fuel from your mains. Holding it at high RPM for a few seconds takes the accel pumps out of the equation. They can mask small mains if you don't hold it there for a bit. Just be sure to let it idle for a minute before you do the test. Starvation due to fuel delivery problems takes longer to happen because you need to draw down the float bowls to make it happen. If you get no pop in the test your mains aren't the issue.

Look hear: http://www.triumphspitfire.com/jets.html

Check out the Fiat jet sizing. The Fiat ran a 40 idf with 125 mains and 210 ac jet with 32 vents an F11 ET. Swapping to a 210 ac jet will lean you up a bit more at high rpm.

I personally think you have a combination of fuel delivery and carb issues.

Here's a shot I just took of my sock and surrounding area. The sock looks crimped and dark to me. See the specs on the floor? The rest of the tank looks unrusted for sure, but the guy kept it filled and Stabil'd, so I'n guessing it should. Whattaya think?
Click to view attachment

I'll do the test later, but since she's fine for a few minutes...even 5-10 and will go close to redline, it sounds (thanks to the education I;m getting from you) like it's more the floats slowing draining down.

Alright...went out to do the "test". I idled her for 3-4 minutes. As I apply throttle, she starts to break up, pop and backfire (seems to be carbs and exhaust) at around 3,000 RPM, and seem to want to freeze at 3,000 or so, and even start to lose RPM. If I just keep punching her further, she seems to get beyond that behavior and rev right on up close to redline where I can hold her for a good bit of time. This is the same as when I drive her...she starts to "eff up" around 3,000-3,500 RPM, and if I just force her , she goes beyond that up to redline.

Transition issues. What size idle jet? Check your float level and bump up your mains.

You are getting a lean transition when you go from idle jet to main jet. You need to make sure your float level isn't low. After that try bumping up your main jet to 125 or 130.

Having a low float level delays when you come on the main jets. Then you pop at @ 3K. If your float level is good bump up your main jets. I personally think they are too small. I'd go with 130's and then go smaller from there. It'll run ok if they're a bit too big. It pops and stutters or you burn up stuff if they're a bit too small.

I'll check the idle jets in awhile and post it. How do I check the float level (11mm) without redoing the gasket, etc.? Can the low float level be because of the sock being blocked or not. What did you think about the photo of the sock and surrounding area? Normal stuff?

I also had stavation and stalling, mind you it was on a 2.0 with FI, but this is the strainer compared to a new one. Not a problem since. $8.

Check my post:
http://www.914world.com/bbs2/index.php?act...t&p=1045406

Changing the sock and fuel line is a good idea. I'd even change out your fuel pump. Unfortunately, thats not your problem. You can't adjust float level without cracking the carb open. You can assume it's fine and go with larger mains and see what happens. You'll be out the cost of the jets if that wasn't your problem. You will have gotten away with not cracking open the carb if it was. I do have to say a lot of guys with lean transition issues seem to be running a 115 main and a F11 ET. Thats what comes in the 40 when they come from Weber. I always wondered why when IMHO the 125 was the more suitable jet. I guess it's so they can sell you more jets.

my tank was way worse than that. You never know that sock could be plugged. I guess if all else fails replace it. It takes a bit of labor but is a cheap fix. The socks are only around 8 dollars. good luck!

Idle jet is a 50.

I accept that the larger jet would be a good move, but keep going back to the fact that the car ran fine from CT to NJ. Then I filled her up with 93 and she started having rpoblems within 20-30 miles. It could be coincidental, but I have to assume that jet size, valve adjustment, etc. had nothing to do with what went sour at that point. I;ve had experiences in the past where the circumstances and evidence were simply wrong, but logic tells me it is a fuel problem...bad fuel (not likely, especially since the problem is RPM specific), or a fuel starvation problem within a specific RPM range. If it runs well at higher RPM than its probably not even the sock. Can it be electrical?

Is it sufficient information to order "125 main jets for an IDF 40", or do I need any more specific information like the full carb ID number?

I agree with you here. This one has me scratching my head. It sounds like a lean transition issue but you would have had it from the start if it was jet sizing. Does it only pop from one carb or a specific barrel? Check the accelerator pump discharge. Are the streams equal and even?

If you want to buy new jets you don't have to get that specific. Just tell them you want jets for an IDF Weber. If your sure it ran great before you might want to hold off spending money on jets and crack those carbs open. You have the parts and the book. If it's worth chancing $30 not to then try the bigger jets.

I'll have to listen to those pops and crackles form the engine compartment instead of the drivers seat and let you know. How do I check the accelerator pump discharges?

I agree with you here. This one has me scratching my head. It sounds like a lean transition issue but you would have had it from the start if it was jet sizing. Does it only pop from one carb or a specific barrel? Check the accelerator pump discharge. Are the streams equal and even?

If you want to buy new jets you don't have to get that specific. Just tell them you want jets for an IDF Weber. If your sure it ran great before you might want to hold off spending money on jets and crack those carbs open. You have the parts and the book. If it's worth chancing $30 not to then try the bigger jets.
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Pull off the air cleaners, look down the carb and open the butterflies with the engine off. You should see a stream shoot down each venturi. Make sure they both look the same and are nice even streams.

Tomorrow...thanks.

115 mains are too small even for a 1.7 IMO.
Get a new sock and get the bigger main jets. Do both at the same time!
That will more than likely make the engine run a whole lot better.
You can consider the rest of the suggested upgrades down the road.

Just ordered the 125 mains. I'm going to do one thing at a time so I'll know better what the issue was (hopefully "was"). I'm pretty sure the problem won't be solved by the bigger mains, just because of the circumstances of how the problem showed up...unless the introduction of 2009 93 octane fuel to her old system really effed with her ability to drink. Now...gotta go out and check the pumps.

OK...checked the accelerator pumps and they are all nice and even. #3 might be a tad less, but even that looks close. So, I fire her up to see where the pops are coming from while watching the barrels. As I'm goosing the throttle, I'm getting gas on my finger from the barrel over piston #1. I tighten up the clamp and she stops leaking. As I'm revving her up, it's obvious that the left bank of cylinders (#1 & #2) are running rough, and the carb pops are coming from the same side. As I continue to rev her I notice what looks like a third emulsion tube emerging! It's the freaking stud that holds down the carb top !!! Guess that will cause some roughness, huh? Tighten down everything and put the air cleaners back on. She's MUCH better (not perfect), and I'm realizing that somebody was probably cleaned out the carbs after the long storage and did a half assed job. I've ordered the 125 mains too. I'll let ya'll know what happens from here. Guessing they need being broken down and put back together with some care.

I'm glad you got it figured out. With the addition of the larger jets and some tuning I bet you'll get them where they need to be. Read the section on adjusting the idle mixture screws and your linkage. Once you get those dialed in you'll be extremely happy with their performance.

Going through the carbs would be wise. Mainly because you'll have an intimate knowledge of the parts involved and how they work. You'll be able to tune and troubleshoot easily.

I REALLY appreciate everybody's help, but especially yours. You've been there steadily...thanks.
Ken

UPDATE...I just drove her for the first time since the tightening up. It's absolutley 80% better. She still seems to starve at certain points and a dose of full throttle punches through that. Also some decel pop that sounds more like exhaust pop than carb pop, though I still get a surprise carb pop every once in a while. The strongest evidence of an ongoing problem showed up when I returned to the garage. In neutral, sitting still, she'll rev all the way up to redline very smoothly as long as she has only been asked to do that infrequently, or after a rest. If I try that repeatedly without a "break", she does her starving act. After my education on here, I;m assuming that's pretty obviously the float chamber not having time to refill, right? If I;' correct, that could be the floats/chambers themselves, or some aspect of fuel deprivation (pump, sock, filter). Am I on target?

Your on target. I would opt for inadequate fuel supply or old accelerator pump diaphrams not springing back quickly. Run the accelerator pump test but pump it a few times back to back. Does it spray nice and even through a few pumps? If no it's time to replace them. If yes then do a hard acceleration through the gears Does it go lean in the higher gears? If yes change the sock and that clicky pump. I'd still recommend bumping up the mains.

Decel pop through exhaust is most likely an exhaust leak.

Thanks...got my list of work.

So...the accelerator pump test went well. I changed the mains to the new 125s. Took her out and she was running so well I took her out on the highway. There were some rough moments but again I could "punch through" them with more throttle. On the way back I jumped off the highway and took a twistie back road route. All of a sudden she started to bog down / starve...couldn't even punch through. Eventually she totally quit on me. Acted as if she were out of gas. Had to get a flat bed ride home (Good old Haggerty insurance). She still has a good accelerator pump squirt, but will not start at all. She has a 1/4 tank of fuel (visually as well as gauge). I;m thinking fuel pump? She still has a click-click-click but it's much quieter and less rapid. CB rotary somebody said?

The clicky pumps slow down and get quiet when they reach pressure (float bowl is full) or have a plugged suction. Good squirt from your pumps means there is fuel in the float bowls. I'm thinking your current problem is ignition related. 12v to the coil? Good spark?

Can you get it to turn over and run a bit on the accelerator pumps or does it not even stumble over?

No idea how to assess whether there's 12v to the coil or good spark.

Take a multimeter and check for 12V on the hot wire to the coil with the ignition in the on position. It'll be a spade type connector.

There are a couple of ways to check for spark. Some might have better ideas. I pull the plug and ground the threads and watch it jump the plug gap or just pull the wire and slide a small diameter phillips screwdriver in the connector and create a small gap between the metal shaft and a grounded part of the car and watch it arc. Either way be careful not to get zapped.

You'll need a partner to turn it over while you check for spark.

Heading out to the garage.

Well...either I'm getting nothing or don't know what I'm doing (highly likely). I have an old multimeter, with an analog type dial. I touched the black lead to what I figured was a decent ground, and tried every one of the six or so spade connections on the coil. Nothing. During the whole time, the fuel pump never stopped clicking (ever so slowly). Maybe the AA battery in the meter was bad...I'll try this again in the AM.

On the older meters you only need the batteries for checking resistance (ohms). Touch the leads together on ohms setting and see if the needle pegs out. If not change the batteries and check again. Checking DC volts should use the circuits DC voltage to move the needle. A test light will work too but you can only see you have voltage not if it's low or not.

The coil will have a + marked on the 12V side. If you have no voltage there with the key in the run position you'll have to trace the circuit and find your problem. Others here are way more qualified than me to help you fix that.

Thanks again.

Change the sock you never know! It looks like yours needs changed anyways. Most likely not your problem but it's the only advise I can give on this one. good luck!

With my limited knowledge I still believe it's fuel related and not electrical. As soon as I figure out a responsible thing to do with 4 gallons of fuel, the tank is coming out...new sock...new fuel pump. Then, if things don't get better, I'll start somewhere else. New coil !

Your car should at least turn over and try to start. Does it cough and sputter and then die? You should be able to run it on the accelerator pumps. If not you now have an ignition problem.

It does not even try to start...no sputter, cough, etc. It does "sound" very different when I'm turning it over when I give it throttle vs. giving it none. Not sure how to describe it, but the tone changes very much. Even though the accelerator pumps are working, there's very little smell of gas like you'd expect. Maybe it's pumping something less than 100% gas?

Probably asked before, but does it try to start with starter fluid sprayed in - I know others say don't use it - but at this point sounds like you have nothing to loose!

Lemme go get some and try. It revs higher when I apply throttle vs. not applying any. Be right back.