HELP !!! 1970 VW Bug - Single Port - 1500cc - Solex H30/31PITC - Stalling when coming to a stop

Car was running fine and then I was coming back from an hour drive and the car started stalling. If you are able to keep giving it gas it stays running--if not the car stalls. It seems to run okay at idle but will eventually die. When driving it seems to backfire and sputter and loses power at times in all gears but first. It's strange because it was driving really well. The coil seems to be leaking a little bit of oil.

The plugs haven't been changed in 9k. ANY HELP ? Please and thank you !

Chad & Camryn (New Bug Owners)

it sounds like you need to adjust the carb

I tried adjusting the carb slightly. The big screw slot is at about 2 o'clock and the small completely vertical. Should I also clean out the top of the carb ?

what i did was turned both screws all the way in and turn them out about 3 turns

I'd do the basic tune-up and see what results you get. Check/Adjust valves, check/adjust point gap, timing, then carb.

Carb tuning instructions can be found here:
http://www.vw-resource.com/34pict3.html (says 34pict3, but will also work for H30/31)

If you don't know how to do valves or points, the same site has instructions for those as well, or let us know, and somebody can give you the quick and dirty methods.

Excellent - Thanks for the help. I'm going to take that advice and do a complete tune up. I'm thinking that I'm going to change the points to an electronic ignition. Is this a good idea ? Thanks for the information.

Also, on the left side of the carb (as you're looking at the engine) is a barrel looking doodad (usually a brass color) with a wire plugged into it. It's your idle air bypass valve. Make sure it's screwed all the way in. Mine came loose one time and it acted similar.

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First thing i would do is take the aircleaner off, and put on a pair of rubber gloves. start it up, and stand in front of the motor. Rev it up, and while its reved up, hold your hand over the carb opening, and completely seal it off, and choke it out till the motor dies. try to hold the throttle open at the same time. a lot of times, if any crap gets stuck in the carb, doing this will suck it out. this has worked many many times for me. if your lucky, it will run great after this. if not:
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like everyone said, start with the basics. adjust your valves, points, and timing. if any of these things are out of wack, even by a little, it WILL run like crap. also change your fuel filter. and for gods sake, if its between the fuel pump and carb, move it to under the gas tank (right before it goes into the tunnel), or atleast before the fuel pump.

as eric said, the quick/ dirty methods:

points: when the points are fully open (turn the motor around till the points are as far open as they will go), loosen the little screw at the bottom that holds the points plate down, JUST A LITTLE, toss a thin piece of cardboard (match book cover, or cereal box) betweem the two contacts, and tighten the set screw. pull the cardboard out, and the gap should be the same as the thickness of the cardboard.

valves: pop both valve covers off. now stare at this pic:



on an actual motor the lifters, are directly opposite of each other. the cam only has 4 lobes, meaning one lobe pushes two lifters. when one lifter goes up, the one directly across from it will be closed 100%, meaning you can set the valve clearence on this lifter. so basically to set the gaps, stare at a lifter. turn the motor till the lifter starts to open, and keep turning just till it starts to close again, turn the motor back and fourth till the lifter seems to be as open as possible. now go the the same valve on the opposite side of the motor and set that gap. keep going till you have all 8 lifters set.

and as far as timing goes, the only way to get this correct is with a timing light. if you don't have one borrow one. if no one has one, then buy one, they aren't too expensive. you can line up the crank with the case half, and match the notch in the distributor, but this method only gets you close enough to make the motor run. it will run pretty crappy til you get a timing light on there and get it spot on. and since the motor is still running, i wouldn't touch timing, untill you get a light.


and yes, i'd defiantely do a FULL tune up. new plugs (copper bosch/ SET THE PROPER GAP, plugs DO NOT come pre gapped!!!), cap, rotor, wires, points, condensor, oil, and DEFIANTELY GET A NEW COIL (preferably a bosch blue coil). try and stick with bosch for everything. a lot of that aftermarket stuff sucks (i.e. BWD, intermotor, duralast, Autolite, Xact, EMPI, scat etc.). Only after all this stuff is done, and set/ gapped properly, should you mess with the carb.

Look and see if the dime sized plug has fallen out of the carb. The plug is on the carb right in front of you when you open the deck lid. If it is missing it will cause the symptoms you are having. You can JB Weld a dime in the hole if it is missing.

chess01 wrote:Excellent - Thanks for the help. I'm going to take that advice and do a complete tune up. I'm thinking that I'm going to change the points to an electronic ignition. Is this a good idea ? Thanks for the information.

Our 68 was doing exactly the same thing as yours. Like Glenn said it was the wire on the idle air bypass valve. Also changed over to electronic ignition. Solved some other issues. Has run great since the change over. I keep an extra under the seat and also keep extra points and condenser, just in case.

So i started with the carb flush and it still cut out. When I had the Air cleaner off I noticed that the Idle Air Bypass Valve was very loose. As someone stated in a previous post. I couldn't real tell how loose it was until I removed the Air Cleaner and gained access. I tightened it up and put some thread tape on it. She runs like a champ and no more stall out. Thanks to all that posted. I feel good about owning a VW knowing such smart people are only a few keystrokes away.