Popping Dell's

I have a CB 2110 with dual Dell's. When I first drove the car after finishing the build it popped at constant speed. The nice folks at CB Performance suggested new larger idle jets which fixed the problem. Drove it a few hundred miles no issues. Next spring drove it some with no issues then it started doing the same thing. This was after installing the carb upgrade kit over the winter. After my 3rd thorough carb cleaning alls well again.

The problem is, it keeps coming back. Sometimes it goes away on it's own other times it doesn't. Last night I drove it to a cruise night on back roads. It was about a 15 mile drive and it ran great. Stayed there about 1 1/2 hours. Drove it through the lot to go home and it's running great. Got on the road and it started popping. Popped down all the secondary roads. Thought I'd go home on the expressway because in the past it will occasionally go away. It didn't. I could feel it lose power for short periods of time. The popping is always at constant throttle or deceleration. It's fine accelerating.

I guess I'll clean them again but this is rediculous. Any suggestions?

Talk to Lane Anderson....

Sounds like the preservative in the gas tank is dissolving and coagulating in the carb jets (or some other crud is getting in there).

Lane had the same problem - had to pull and clean the gas tank and flush the lines and clean the carbs to finally cure it.

gn

I also have had it reoccur lately due to flooding the carbs with rain water. All the loose crud on the air filters and around the top of the cars got into the floats and all the tiny passages, and occassionally causes spitting and farting (of the car). I need to disassemble the carbs and clean them thoroughly to remedy the situation.

Ron, how old is your gas tank, and how old is the gas in it? How many miles since completion? Also, have you washed the car recently, possibly getting water in the carbs? The answers here could point in different directions with similar symptoms.

Gordon and Lane,

I don't drive the car in the rain (no top) so I have never sprayed water on the car or in the engine compartment. Just California Duster and spray detailer for bugs.

The tank was purchased in 93 when the previous owner purchased the kit. It never had gas in it (that I'm aware of) before I completed the kit 2 years ago. I don't think it was full when I stored it last winter (rust?) but I have an in line fuel filter right before the electric fuel pump.

The car isn't driven much. Maybe 750 miles since completed. Frankly I haven't had the confidence to drive it very far with this popping thing.

Hmmm... It sounds like it's either what Gordon described as happening to me, or you're getting debris in from something. Could be rust, I suppose.

Was your tank inside painted or coated with something intended to stick around? If not, it probably had the cosmoline stuff intended to prevent rust, but also to dissolve in gas. If you don't run a lot of gas through it fairly quickly, the goop will coagulate in your fuel system, trapping other crud along with it. If that's the case, the only way to fix it definitively is to:

1. Remove your tank and have it throughly cleaned inside
2. Remove, disassemble, and clean your carbs
3. Replace all fuel filters
4. Replace all fuel lines that can be removed
5. Flush out any fuel lines that can't be removed
6. Reassemble everything
7. Adjust carbs

Yeah, it's a real bite in the butt. You could try running some fuel injector cleaner through the system to see if that helps. I'd try that first, for obvious reasons. Pour in a bottle of Techron, fill up the remainder of the tank, and drive it quite a bit to flush things out. If things don't improve, I'd tend to believe that you have to do the whole enchilada. However, my car has Webers, and I don't know if Dells are as prone to this sort of problem. Anybody else have ideas? It really does sound like crud in the fuel, and no, it shouldn't happen this often.

Thanks Lane,

I'll try the cleaner a few times. I don't like the sound of the big fix.

Ron....In your opening statement, you said the problem returned after installing a carb up date kit.....If the kit included larger Venturi, there is the remote possibility your fuel air ratio is off scale a little.....I run Webers so this may or maynot apply,...Try backing out on the mixture screws an additional 1/2 to 1 turn from where the engine smooths out......If you don't have a "trash" problem, this might help....

Just a thought....

Thanks Leon,

The thing is that 75% of the time it runs fine.

I found that if you want to set the mixture right, the engine has to be really warm. Then richen each screw 1/8 turn from peak rpm. Then forget about them. Cured my problem w/popping after I got water in the bowls and cleaned it out. I left the carbs on the car and removed the tops. Don't try this on the Speedys, I can get away with it on my Spyder. Since Carlisle, the car hasn't missed a beat, I fixed it just before. Had a plugged idle jet on the way to dinner at Caddyshack, cleaned it out at the gas station, and smooth ever since.

And make sure that the linkage between the carbs is disconnected when you adjust them. That way you're not adjusting them both without knowing it.

Thanks Dan, It was running really good when you gave me a ride!

Speaking of Carlisle, Pearl was running GREAT all through Carlisle (rain and all) and then ran crappy when I took her out after we got home (just like right before we left Beaufort).

Replaced the intake manifold gaskets twice and finally got her straightened out this week. Went out for a ride last night and the A/F mix was about 13.8 (good for her) and she's finally gotten over the puking on decel.

Now I'm heading over to Worcester, MA this weekend to see what's cruising around downtown for the so-called, "Street Rod Summer Nationals". It used to look like "American Graffiti" out there, but in recent years has become a Muscle Car Love-in.

Gordon
The "Speedstah Guy" out huntin V8's

Gordon - Happy Hunting!! Yeah Baby!!

You guys all have fun. I'm up in Asheville for the long weekend - without the Speedy, unfortunately. I'd love to have it on the roads up here. We'll get our thrills on Saturday when we raft section IV of the Chattooga, where they filmed "Deliverance". I'm just hoping I don't get Ned Beatty on my raft.

Keep an eye on the tree line.....There be Vultures there.....

...do I hear a banjo playing?

... So after you figure out which side is making the noise, check a couple things. First, take off the air cleaner and have a good look inside it. If it's clean and clear, with no particulate stuff inside, give it a sniff and see if it smells like fuel. If the carb has been popping, making that PSSST noise, there might be a little residue in there. Fuel doesn't generally backflow through idle jets, but your main jets could allow it.
Second, get out your long tweezers, a wire-tie (from a loaf of bread) and a standard screwdriver. Look down inside the carb, between the aluminum stacks, and see the two little brass screws that live at the bottom of the valleys in there. Turn those guys counter-clockwise and grip them carefully with the postal tweezers. Pull them out, and take the two pieces of each jet apart. They'll look like one piece, but they come apart at the indented groove.
I usually use my teeth. Strip the paper or plastic off the bread-tie thingie, and use the wire itself to ream the nozzle piece and the four-way ventuir holes in the jets, then snap them back together.
Repeat for the remaining one on the carb you're attending to, and maybe the other one for good measure. ...

Dells are quirky, Ron. I have a few ideas for you, and I'm quite sure someone else here can give you the rights and wrongs of balancing carbs -- I only know what I do with mine and what works for me -- but this may help.
Dual Dells mean you have to really keep an ear out for trouble, but after a while you learn what the noises are, if not what they actually mean.
A few things jump right out at me. You say you don't hear the popping on acceleration. When you've got your foot in it, the carbs are pulling a lot of air and a lot of fuel; popping then would indicate that something's preventing adequate mixture of fuel and air on the sending side of the main jets or in the jets themselves -- or that something isn't bolted tight enough (either the carb to the manifold or the manifold to the head). That isn't the problem, right?
You say it's prone to happening at constant speeds and on deceleration, but you stop short of calling it a backfire; we'll assume that you're not hearing mini-gunshot noises, but instead it sounds like popcorn in a popper. You hear it rather than feel it as you cruise?
If it sounds like a silenced pistol in a Mafia movie, you might not be able to tell which side of the car it's coming from while you're driving, but I'll bet it's the idle jets in one carb or the other.
If you duplicate the rpms in your driveway with the car in neutral and the brake set and the engine hot, you'll be able to tell if it's one side or the other. Maybe then, you'll only have one side to worry about, and not both. ...

... While you're back there, if you have the tools and you're turning mixture screws, see what kind of vacuum they're drawing with a synchronizer. Inexpensive tool, and very handy.
You'll probably want to synchronize them and make the draw somewhere between six and a half and seven pounds of vacuum at 1,000 rpms -- where it should idle nicely.
I do mine that way every time I switch jets, and it runs a little rich to keep the temperature down a little.
I agree with turning the screws an eighth of a turn as you adjust them, but I'd add that you should know where they are right now before doing that. They might not all be set the same as they are right now -- so be sure to get a baseline first.
Also, you said you know the tank was more or less unused when it was installed, but did you put an air line on the hard-line through the tunnel before you put lines on each end? If there was rust in that line, it might be slowly sending tiny flakes of rust into your filter and jets. Not such a bad deal on acceleration, but if it's sputtering as you cruise along, those flakes would be enough to clog the idle jets -- which are your primary fuel delivery nozzles at cruising rpms.
My two cents. Hope maybe it helps. Lots of guys here know more than I do about this stuff.

One last thought for you. Check the terminals on your distributor and make sure they aren't corroded. If they are, hit them with the old wire brush until they're shiny again, then put the plug wires back on tight. That might be the simplest fix ever.
Good luck!

Thanks Cory,

The popping is like popcorn not a backfire. For good measure I get the occasional pssst at speed too. I do feel an occasional surge / loss of power at constant speed and yesterday some sluggish acceleration. It will also pop at idle.

I assume the screws you want me to take out are the idle jets. I had them out yesterday and could see light through them but blew them out to be sure. I have a sync gauge and will double check. I'll also check out all the carb and intake mounting bolts. I haven't spent a lot of time setting the mixture screws so that's probably a place to look too.

The hard line had never had gas in it when I bought the car so I don't think that it should be a problem. I'm uncomfortable with the condition of the tank. It was clean when installed but I can see some light rust inside.

My mixture screws tend to live at about three and a quarter full turns out. Sounds like you're on the right track.
Sorry about being so vague with the idle jets - you guessed right. Where I spelled 'ventuir,' I meant venturi. Oops.

Ron, I assume you have the CB Perf. book for Dells. On pages 54 & 55 shows how the air/fuel gets to where it needs to go. Good stuff.

As fuel tank, lines and delivery were all touched on, the only thing I'd add is a metal can type filter where the fuel line exits the pan in the rear(not in the engine compartment).

Where the air comes in may be a fault, too.
Looking at where the jets are, you'll see they live in a "bathtub" like depression. Excellent place for any and all dirt to gather.
Now look between the jets and you'll find a hole in the bottom with a brass tube in it. I call it the (bathtub) "drain". This hole is the air inlet for the idle jet and can get clogged very easily, especially when squirting carb cleaner at the jet holes. Whilst you have the idle jets out, it's not a bad idea to be sure this port is blown out.
Can't understand why they don't project the brass tube up in the air a bit so as not to get dirt blown or sucked down it so easily. Next time I have my carbs pulled I'm gonna look into this.

~WB

Thanks for all the help. I ran it for about 25 miles with carb cleaner in the gas. I know it's not much but it didn't help. Yesterday I tore the carbs apart almost completely AGAIN. I'm getting pretty good at it. Less than 2 hours. The only thing I don't mess with is the accelerator pump. I used spray parts cleaner and an air gun with a rubber tip so I can concentrate the blast. Put them back together and it runs fine. I really couldn't see any debris. I did check the little filters that are at the fuel inlet in the carbs and they were very clean. I would think if was a gas tank rust issue I would see something there.

I did make sure to blast the holes in the bottom of the bowls.

I really have to put some time in adusting the idle screws next. I don't have a tuned enough ear for that. I have an old dwell meter with a tach setting that I will try to use.

Again thanks for all the help. When it comes back again (not too confident am I) you guys have given me a lot to look for. I'm in the middle of getting my son's 53 Ford pick up ready to paint. When that's done I'll have more time to figure out this mess.

Ron, That's what gets me. I can never find the dirt during cleaning, but after reinstalling, the car runs fine! Must be some microscopic crap that gets in there. I have a second filter in the rear and my carbs internal filters come up clean except for a few specs. I just wonder if the air circuits aren't the culprits sucking in the crap.

~WB

Yea Bill, There was no sign of anything. I even have the extended idle jet tubes. I can't imagine that stuff by-passes the filters.

Ron,
I have Dells, and I have become pretty good at working on them. Primarily that's because I kept working on the carbs to fix problems that the carbs didn't cause. Through this, I've learned the big Dells are pretty bullet-proof and easy to get right.
You are at a point now where the engine seems to be runninng right. By this I guess you mean that you used a snail to balance the carbs at idle with one carb's rod-eye link disconnected, then maintained the same balance at idle after reconnecting the link (and not adjusting either idle screw on the carb), and then checked the balance at 1800-2000 and corrected it if necessary by adjusting a rod-eye link.
I guess you also mean you can drive around without any misbehaving "back there".
If that is all true then you have ruled out a whole bunch of things that would tend to be constant (like off-idle balance, leaky gaskets on manifolds, timing / ignition issues, etc.). So you can wait and see what happens next:

I've had symptoms like yours that weren't caused by the well advertised clogged idle jet (I suppose main jets can clog, but they have relatively big holes).
My most difficult to diagnose "carb problem" was broken motor mounts. I replaced EVERYTHING in the carbs, including floats. But still when I drove over rough road the engine would pop and sneeze and generally snot around. It only happened at steady rpm driving (2000-2500) and I'd generally have to tromp the throttle to clear it. I knew it MUST be carbs because I had completely replaced the ignition. As it turned out I found the shattered mounts by accident (red urethane mounts -- don't buy 'um). The shattered mounts allowed the engine to jitter up and down on the bumpy roads and rapidly jiggle the the throttle linkage open and closed. It doesn't take much of that before pretty soon she was coughing, gagging, popping, chuffing and generally carrying on. So I'd go home and rebuild the carbs again.
Eventually I discovered the motor mounts -- and that took care of that!

Then there was this "carb problem": I'd romp through a few gears of red-line thrill seeking on freeway onramps and then settle down to normal speed in 4th. Then (my reward for all that fun) it would start popping and snarling at steady freeway speed. Of course I was sure I sucked something into the jets so I'd pull over to blow them out or limp home to (what else?) rebuild the carbs. Which ever I did, it always seemed ok after that; until the next onramp romp.
In the end my "carb problem" was actually a restricted fuel pressure regulator. But it could have be just as likely a flakey fuel pump (especially if it was a mechanical pump or one of those noisy Facet electric pumps).
The problem was that I'd empty the bowls during the romp and the bowls couldn't refill again faster than required to supply fuel for 2500-3000 rpm. Thus, I was fuel starving (just like clogged jets). The problem would go away after my "repair" because at idle the supply was enough to fill the bowls and sustain just enough flow for under 3000 driving.

So there are a couple of off-the-wall things to remember. Check your mounts and (if you have an electric pump like your should) see how long it takes to fill a quart jar.

Crap, with all this carb talk, mine started acting up...got the pops and farts. Pulled each wire...#4 nothing at idle. Mains worked great. Pulled the mixture screw and jets and shot 'em with carb spray and air. She came right back to life. Thanks to the car gods. I'm triple filtered and can't for the life of me see any dirt. I guess a tiny speck is all it takes. They are really easy to work on though.

~WB

Mark, I'm going to print those notes and add 'em to my folder!
Good stuff -- especially about the red urethane.

Mark, I thought I replied to your note but it isn't here.

I agree with Cory. Good Stuff! I need to follow your description and do a good job of adjusting the carbs. I don't have the ear for doing the adjustment without a tach and the tach in the car is not that accurate. I think I have an old dwell meter/tach that I can use.