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Wed Dec 02, 2009 5:40 pm

hello im going to try to explain this so please bear with me here. My bus has been running and driving perfectly for the last 4 months. But 2 days ago it has been acting up. it idles rough, before it warmed up. but after that if i give it gas it sputters and backfires when i let off the accelerator pedal. today i readjusted idle ad got it to stay running but it still wants to shut off on me. when i drive it when i put it in first or reverse and accelerate it boggs down, but as soon as i hit the gas again the rpms shoot up and it takes off. any suggestions?

Wed Dec 02, 2009 5:57 pm

It sounds like one or more of the idle jets are clogged, if you do no have CB's jet doctor kit this may the time to order one or modify your idle jets.

Phil

Wed Dec 02, 2009 5:58 pm

vw_bud wrote: hello im going to try to explain this so please bear with me here. My bus has been running and driving perfectly for the last 4 months. But 2 days ago it has been acting up. it idles rough, before it warmed up. but after that if i give it gas it sputters and backfires when i let off the accelerator pedal. today i readjusted idle ad got it to stay running but it still wants to shut off on me. when i drive it when i put it in first or reverse and accelerate it boggs down, but as soon as i hit the gas again the rpms shoot up and it takes off. any suggestions?

clogged idle jet?

Wed Dec 02, 2009 6:06 pm

that sounds about it. i was warned about the ups and downs of dellortos. i even think its the dreaded "dellorto-drip."

Wed Dec 02, 2009 6:12 pm

Dell's are the best dual throat carb for VW's in my opinion, much better then Weber. I have been running these carbs for years and I call them the set and forget carb because when they are correctly set-up they will run and run without any adjustment or problems. So take your time, learn everything you can about them and enjoy some good engineering.

Phil

Wed Dec 02, 2009 6:16 pm

yea, ill get it eventually. if not vw can help me out im going to school for them in august.

Wed Dec 02, 2009 9:02 pm

you can kind of check whicj carb by cupping your hands around the top and creating an artificial choke. If you move your hands in to choke it and it speeds up then that carb is too lean. While this may not solve your question, you can use it troubleshooting to help locate where the problem is. A mirror and small flashlight can be used to look down the barrels when the engine is idling. If one of the carbs is pouring fuel and the other is not, that can be your problem. Another remote possibility would be a sticking mechanical advance or a bad vacuum advance on the distributor so make sure the distributor advances smoothly. Anything that creates a bad vacuum leak can also cause backfiring like that. Whip618 gave a very valid cause and solution also.

Wed Dec 02, 2009 11:23 pm

I always check for intake leaks. if that doesnt turn out, id readjust and synch carbs.

Thu Dec 03, 2009 8:53 am

Before you do anything,make sure your linkages didn't get out of adjustment. Them lock nuts tend to loosen and get the link out of rig. withthe motor off, go to full throttle by the center of the arm. do both carbs hit the stops at the same time?? then go to off and make sure thay hit at the same time. Make sure that the ends of the shaft aren't too wobbly also.
If that is good,then remove the idle mix screws and emulsion tubes. clean them good.,and down the valleys. Dells are very sensitive to dirt and debris.
Resynchronize after complete.
It is sputtering because one side is getting fuel,the other side is lagging.(flooding) Backfiring because one side has too much gas and the other side is ...lagging(burning off excess)

Wed Dec 30, 2009 8:07 pm

well i finally got the carb sync. and it was running fine all day in 2nd through town, and me and my girlfriend were enjoying its running but since late summer i cannot downshift from 3rd to 2nd. and when i finally got to 3rd i usually let it coast i neutral until i can get into 2nd and while it coasts it stalls out. any ideas?

Wed Dec 30, 2009 8:34 pm

what were the carbs pulling? i set mine at 5kg. check your timing and i even invested in a Tach. i was close idling at 950 rpm, i like 1000 a bit more and it does not feel like it wants to die anymore.

Wed Dec 30, 2009 9:33 pm

running 40dellls I can get my idle way down if i feel good, had it at 450 once, but have been unable to recreate. 850 is not an unreasonable idle speed, and with a tight exhaust it sure sounds great.

Thu Dec 31, 2009 12:15 pm

For what it's worth, I was having some strange problems with my Dells recently. They bus would run fine when cold, but once warm, got really, really rough. After about the sixth time of adjusting and synching, I notices a gas stain forming between the halves of the carbs, where the top chokes bolt to the main body. Sure enough, the two halves were just loose enough to expand when warm, throwing off the mixture. Fixed that and I'm right as rain again. Dells are excellent carbs.

Tue Feb 02, 2010 11:18 pm

ok so i paid $50 to be towed 6 blocks........ugh i went to fill my bus at the station and it wouldnt start at all it would spin over nicely and even push starting it wouldnt fire. and its really cold here in PA so i am stumped, anyone had this happen?

Wed Feb 03, 2010 3:49 am

Gotta be fuel or spark, pretty simple. Fuel pump quit? Points/condenser/coil quit?
Whatd you find?

Wed Feb 03, 2010 4:15 am

mightymouse wrote: Gotta be fuel or spark, pretty simple. Fuel pump quit? Points/condenser/coil quit?
Whatd you find?

I agree. That dwell meter is about to pay for itself. Make sure the fuel pump is getting 12 volts to it and it is not powered up from the coil.

Thu Feb 04, 2010 2:32 pm

ive had this happen before and it was just the dellortos acting up. its snowy here and i fix vws and i just dont have a garage so im letting them deal with it i want to see what they know.

Sun Feb 07, 2010 8:49 pm

again of all things to happen. my dellortos are fine but the linkage is being weird. on the left carb, the linkage is pushing the butterfly valves open and the bus is revving for some reason it looks like the return spring is not at fault but the linkage is stripped or came loose on that side.......again any ideas?

Sun Feb 07, 2010 10:31 pm

fix it.....

whatever is stripped or bad, just replace it. Synch the carbs at idle, then make sure both are opening at exact same time. Good to go.
Whats the issue?

Mon Feb 08, 2010 11:25 pm

what is the name of te spring on the end of the carb that is on the shaft with the idle speed adjusting screw? the spring sits behind this and then the end connects to the linkage.