The saga continues...., #3 cylinder not warming up, lean AFR Options

[TheCabinetmaker]

Any time something happens just after I do some maintenance I look back at what I just did and go do it again. It usually works.

[era vulgaris]

It feels like lately anytime I do any maintenance, something happens (IMG:style_emoticons/default/laugh.gif)
At least I'm working all the bugs out. The car was soooo awesome on tuesday! Once I get this idle circuit cleared I'll HOPEFULLY be good to go! (There needs to be a 'knock on wood' emoticon for when you get too optimistic about how good your car is running)

[era vulgaris]

So I've removed the carb and disassembled it twice now. Both times I've blasted air through the idle circuit passages, and all the other passages too. I studied the cutaway drawings in the Dellorto book to see where the passages lead to, and I'm able to tell that air is moving through the passages to where it's supposed to go. But still I can't get any response from that idle mix screw.

I think I'm going to try soaking the carb in something, and maybe that'll loosen up whatever's in there. Is there something strong you guys might recommend to soak it in that'll really clean out every little bit of it?

Or is there something else I should try first?

I've just about had it with these damn Dellortos. I've never had this much problem with a carburetor.

[MarkV]

I had a problem with one of my Dellorto idle screws not responding. When I rebuilt them the problem went away. My carbs got water in them before the rebuild to the point that the spring in one of the diaphrams rusted in two. I soaked mine in Beryman Chem -Dip carbureator cleaner. Then I soaked them in Simple Green and water to neutralize the Beryman. Blew out all of the passages with spray carb cleaner and compressed air. There is some pitting on the inside of my carbs but they have worked fine for years that way. Once they are rebuilt and set up you shouldn't have to mess with them.

[era vulgaris]

I had a problem with one of my Dellorto idle screws not responding. When I rebuilt them the problem went away. My carbs got water in them before the rebuild to the point that the spring in one of the diaphrams rusted in two. I soaked mine in Beryman Chem -Dip carbureator cleaner. Then I soaked them in Simple Green and water to neutralize the Beryman. Blew out all of the passages with spray carb cleaner and compressed air. There is some pitting on the inside of my carbs but they have worked fine for years that way. Once they are rebuilt and set up you shouldn't have to mess with them.

Unfortunately I just rebuilt them. I got one good day of driving out of them, where they performed perfectly, before this happened. Are those dips safe for brass? I'd rather not pull the throttle plates off if I don't have to.
Is there by chance an additive or something I can put in the float bowl that might help clear out any blockages?

[Series9]

One side of the engine having a problem tends to be a carb (on a dual carb engine).

One cylinder having a problem tends to be valves, compression, spark plug or ignition for that cylinder.

I would check:

Compression first.
Valve clearance second.

[Series9]

Then, swap plugs and wires on that side of the engine.

Then, change the distributor cap and rotor.

I've seen many spark plugs that looked great, but didn't spark.

[Series9]

Swap idle jets, main jets, emulsion tubes, etc around between the cylinders and see what happens.

[ThePaintedMan]

(IMG:style_emoticons/default/agree.gif) With Joe. You already did the comp test. You already rebuilt the carbs. You already changed plugs and wires. Let's think back to how this problem started - it was running fine, then it stopped running correctly. Typically carbs don't just all of a sudden stop working EXCEPT for a plugged idle jet.

If you're SURE the idle jet is clear and there isn't some mystery debris behind it, then I'd be leaning towards an ignition issue. As Joe said, try swapping stuff around. Maybe try swapping #3 and #4 spark plugs. Did the issue follow it? If no, try swapping out another used plug wire on #3.

Also, is that spark plug on #3 wet? I mean, is fuel visible on it after you idle it for a few minutes? That is a dead giveaway that it's an ignition problem. If it was a plugged idle jet, the cylinder should not be receiving fuel and should not, in theory, be wet.

[era vulgaris]

One side of the engine having a problem tends to be a carb (on a dual carb engine).

One cylinder having a problem tends to be valves, compression, spark plug or ignition for that cylinder.

I would check:

Compression first.
Valve clearance second.

Then, swap plugs and wires on that side of the engine.

Then, change the distributor cap and rotor.

I've seen many spark plugs that looked great, but didn't spark.

Swap idle jets, main jets, emulsion tubes, etc around between the cylinders and see what happens.

All of that has been done and/or tested, see page 1 of this thread. The only thing I can't do is swap wires because the MSD wires from Tangerine are cut so specifically to length that it's impossible. But I have verified it works by pulling the wire while the engine was running and letting it ground to the shroud. What a funny fuzzy feeling in my hand! (IMG:style_emoticons/default/smoke.gif)

(IMG:style_emoticons/default/agree.gif) With Joe. You already did the comp test. You already rebuilt the carbs. You already changed plugs and wires. Let's think back to how this problem started - it was running fine, then it stopped running correctly. Typically carbs don't just all of a sudden stop working EXCEPT for a plugged idle jet.

If you're SURE the idle jet is clear and there isn't some mystery debris behind it, then I'd be leaning towards an ignition issue. As Joe said, try swapping stuff around. Maybe try swapping #3 and #4 spark plugs. Did the issue follow it? If no, try swapping out another used plug wire on #3.

Also, is that spark plug on #3 wet? I mean, is fuel visible on it after you idle it for a few minutes? That is a dead giveaway that it's an ignition problem. If it was a plugged idle jet, the cylinder should not be receiving fuel and should not, in theory, be wet.

It's not a plugged jet, idle or main. I've swapped them around like musical chairs. There's never anything in the jets when I pull them except for fuel. What I do think it is, is a plugged/restricted idle circuit. Somewhere in one of the fuel passages in the body of the carb, something is hindering fuel flow.

I've swapped plugs around too. I even bought four new ones and tried them all. Plug isn't wet. I think the cylinder is getting no fuel, or not enough fuel, while at idle.

[ThePaintedMan]

Okay. Now I'm tracking. Plug is not wet and you swapped others out, then I believe you're on the right track. It's likely a carb issue. Dellortos are fairly simple inside, but there are ways for them to get stopped up. It's far more common of Dellorto 45s, but there is a known problem called the Dellorto drip whereby a lead plug falls out in the main circuit an essentially allows fuel to drip into the throat at all times. However, your problem is opposite though it's conceivable that the opposite could happen if the plug dislodged in the right way.

http://www.thesamba.com/vw/forum/viewtopic.php?p=4836570

The only other thing I can suggest at the moment is to plug up the main circuit as best you can when you go to blow out the idle circuit and try to force as much air through there as possible, to blow out any crud that might be in there. You could also dip the carb, but instead, if you could isolate/plug the idle and main circuits, you might be able to inject Berryman's B-12 right into that circuit and let it sit. Then you don't need to worry about that stuff getting into the throttle shaft bearings.

[r_towle]

Remove and rebuild that carb, again.

Check to make sure the,gaskets,have all the correct holes in them.

[era vulgaris]

Okay. Now I'm tracking. Plug is not wet and you swapped others out, then I believe you're on the right track. It's likely a carb issue. Dellortos are fairly simple inside, but there are ways for them to get stopped up. It's far more common of Dellorto 45s, but there is a known problem called the Dellorto drip whereby a lead plug falls out in the main circuit an essentially allows fuel to drip into the throat at all times. However, your problem is opposite though it's conceivable that the opposite could happen if the plug dislodged in the right way.

http://www.thesamba.com/vw/forum/viewtopic.php?p=4836570

The only other thing I can suggest at the moment is to plug up the main circuit as best you can when you go to blow out the idle circuit and try to force as much air through there as possible, to blow out any crud that might be in there. You could also dip the carb, but instead, if you could isolate/plug the idle and main circuits, you might be able to inject Berryman's B-12 right into that circuit and let it sit. Then you don't need to worry about that stuff getting into the throttle shaft bearings.

Dells have lead plugs that can dislodge?! Goddamn, I like these carbs less and less the more I get to know them. One more thing to worry about. That cutaway is great though. I guess I'll disassemble this carb for a 3rd time and blast all the passages out again. I'll try as you suggest to build up the pressure.

Rich, the gaskets are the same on both sides.

[rhodyguy]

When you blow air thru the idle jet, out of carb, do you blow opposite of the direction of flow? Cans of compressed air work swell for blowing out passageways. Not so much pressure or volume but the plastic straws get up inside of the passageways. Hate to say it but it might be the time to send them out to a pro service. You certainly don't want to damage engine internals chasing a carb issue. The spark plug is completely dry after running the engine at a high enough rpm to get off of the idle/transition circuitry?

[JOEPROPER]

Try to artificially enrich the effected cylinder to verify your suspicions of lean mixture. You are doing a lot of work, and seems like repeatedly, before the problem is verified. If lack of fuel is the problem, this will temporarily solve it. The safest way I believe is to use propane enrichment. Hope this helps.

[ssuperflyoldguy]

I'm feeling your pain. Can you switch carbs side to side? Maybe someone can loan you a carb. Another thing to consider is a valve sticking in the guide. I had a lawnmower that gave me fits to keep running - switched to a synthetic oil and valve train moved better after that. Just a thought

[era vulgaris]

When you blow air thru the idle jet, out of carb, do you blow opposite of the direction of flow? Cans of compressed air work swell for blowing out passageways. Not so much pressure or volume but the plastic straws get up inside of the passageways. Hate to say it but it might be the time to send them out to a pro service. You certainly don't want to damage engine internals chasing a carb issue. The spark plug is completely dry after running the engine at a high enough rpm to get off of the idle/transition circuitry?

I've been blowing air through the passages from every direction that is possible. I've been using the cans of compressed air. Yeah the nozzles are great for getting all up in there!
I've got it apart right now. I just ran carb cleaner through every passage, and verified that fluid can move through all the passages, then blasted it out with the canned air. I'm letting it dry out before putting it back together and reinstalling. If it doesn't work this time, then I don't know.
I remember reading somewhere that there's a guy, I think it was in Utah maybe that people send their Dells to. Anyone know his contact info?

I haven't tried revving the engine up, just for fear of doing any damage. I guess it might be worth it to see if it starts firing once it transitions to the main circuit.

Try to artificially enrich the effected cylinder to verify your suspicions of lean mixture. You are doing a lot of work, and seems like repeatedly, before the problem is verified. If lack of fuel is the problem, this will temporarily solve it. The safest way I believe is to use propane enrichment. Hope this helps.

I'll give that a try if it doesn't work this time. Gotta go buy some propane first.

[rhodyguy]

The Utah co WAS A.C.E. (Air cooled engineering). The owner sold it and it is/was still in operation under a dif name. I think the same techs. I had some 44s redone and smaller venturis install there. Very easy to deal with. Eric Shea or Jeff Hines might know the new name.

[ThePaintedMan]

I've got a set of Dell 40s here that I'm going to rebuild, including pulling the plugs out and replugging the passages. No timeframe on that yet, but I'm going to write a how-to, sort of like I did for the Webers. If you're adventurous, you can tackle this yourself as well. Or if you can't get a hold of A.C.E. (who had a great reputation as I understand it), I can take a look at the offending carb for you. I am a new dad, so my time isn't "free", or all that plentiful, but I'll do my best if you decide to go that route.

I would say since you've gone through the trouble of pulling them off again, how about one more try back on the engine? This time, swap that carb to the other side. If the issue follows it, it's 100%, positively for sure an issue with the carb.

[era vulgaris]

I just put the carb back on and still nothing on that cylinder. Zero response from the idle mix screw. I just don't get it. I watched carb cleaner fluid flow through every passage. I positioned the carb to test each fuel passage, and carefully metered carb cleaner through so I could visually verify that each passage was allowing fluid through. This doesn't make any sense. Is there any other issue that would cause the mix screw not to respond?

I'll try swapping the carbs later today or tomorrow. I need to walk away for a bit. I'm so frustrated with this car right now.

I need to figure this out soon. This car is my only car. I'm lucky that I work from home and that I can borrow my girlfriend's car after she gets home from work if I need to run an errand. But I've basically been without a car for a month now between this and the vac leak I had on #2. I'm just about at the point where I'm ready to buy a new set of carbs and call it done.

There's no possible way this could be a valve issue right? The compression test wouldn't have shown compression if a valve was stuck, right?

A search turned up ACE is now Blackline Racing. I'll contact them and see what they say.