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Spitting Carb on my Type 4

 
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71_georgia_beetle



Joined: 28 Mar 2008
Posts: 440
Location: Grayson, GA

1974 Volkswagen Westfalia

PostPosted: Mon Dec 08, 2008 9:58 pm    Post subject: Spitting Carb on my Type 4 Reply with quote

I had some issues with Winni and thought I'd share. We left for home one night and half way back she started spitting (backfiring) through the carb. At the end she would only stay going with the pedal depressed and pumping. Short story long, she had a tit on the points, one fouled plug, and the fuel pump wire had one strand left on it. Not sure which one or all caused the problems. I got everything corrected and did a full tune up as well as pull the carb, clean jets and inspect.

The carb seemed fine but I noticed that the full range of the carb was not being utilized. The throttle lever on a progressive conversion is center and angled to the left to compensate for the staggered cylinders. The throttle cable exits the tube through the rear tin about 8" to the left of the carb if looking from rear to front. If you were to hook this up as is, the cable would be pulling from the side and not actuate the throttle lever at all. To counter this the PO had bent the throttle lever out towards the cable. This allows you to connect the cable and get about 70% swing out of the lever.

I fabricated a new lever and everything worked as it should and I had 100% range of motion on the lever. When I started the engine it idled a little rough for 30 seconds or so and puked up a huge plume of white vapor gas and died. I fiddled farted around with the carb to no avail. As suggested buy Clyde, it might be timing. I had planned to time it but needed to keep it running in order to do so and to get it to temperature. The last straw was 2 second after i pulled my face away from the above access she blew a huge puff of vapor that this time ignited and the fire ball rolled along the roof of the bus so..........................I sat down, took a deep breath and reviewed. I tweaked the dist around just a bit, tried again and she started and stayed started. Then she revved to 2500 and held, I twisted the dist just a hair and she almost died, twisted back and she idled good for a second then revved 3000, farted out of the carb and died. WTF is going on here?

Two things. I was trying to time an engine with a fully locked choke and a partially open throttle, so as I would change the timing the choke would kick in to full rev and on and on and on. When I put the choke back on I set it at factory zero but when you have a Weber carb and an incorrect Holley choke, zero won't cut it. This coupled with the fact that when I fabricated the new lever I let it drag on the intake manifold just a bit so it held the carb open just a bit.

I guess the moral of the story is, sometimes you just need to step back and take a 20 ft view and review before zoning in on one thing. I could easily see where I could have chased my tail.
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71 Standard Beetle "Big Bird"
74 Westfalia "Winifrid"
Burel Photography
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