66 Beetle, Backfiring out of Carb on Acceleration

Beetle, Karmann Ghia, Thing.

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wdollie6
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66 Beetle, Backfiring out of Carb on Acceleration

Post by wdollie6 » Sat Sep 04, 2021 9:54 am

My prized 1966 beetle, original 6 volt, 1300 beetle. has developed a backfire on acceleration, out of the top of the carb! I have checked valves (right on), points (right on) and timing (off slightly) and rebuilt the 30 pict 1 carb but no improvement. I have verified fuel flow through the pump and ensured that the acceleration pump on the carb was providing a consistent stream of fuel through the brass elbow in the carb., also ensured it was pointed properly. Nothing I have done has improved the situation.

Help!

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wdollie6
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Re: 66 Beetle, Backfiring out of Carb on Acceleration

Post by wdollie6 » Sat Sep 04, 2021 9:56 am

... and yes during the carb rebuild I ensured that I removed the two balls, cleaned and that they rattled upon reassembly..

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Re: 66 Beetle, Backfiring out of Carb on Acceleration

Post by wdollie6 » Tue Sep 07, 2021 6:13 am

Found the problem, throttle shaft bushing on drivers side was worn out. Sprayed carb cleaner in that area at idle and clearly the bushing is worn, all other areas, manifolds, etc. were fine. So off to Volksbitz for a rebuild. My son and I temporarily put a 30 pict 2 in its place but it is worn as well, functional but sloppy. Unfortunately the 6 volt doesn't manage the 12 volt choke well so it takes a while to come off choke, in reality never does because the choke shaft is sloppy as well, bushing is worn. Idle has been a challenge on this carb vs. the 30 pict 1 which idled well but had a long dead spot during acceleration.

Probably should consider rebuilds of the fuel pump and distributor as well as these have never been touched, the engine ran great from day 1, quite a few years ago now.

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wdollie6
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Re: 66 Beetle, Backfiring out of Carb on Acceleration

Post by wdollie6 » Tue Sep 07, 2021 6:14 am

Actually had to look back, purchased her in 2005, time has flown by...

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Amskeptic
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Re: 66 Beetle, Backfiring out of Carb on Acceleration

Post by Amskeptic » Sun Oct 24, 2021 6:06 pm

wdollie6 wrote:
Tue Sep 07, 2021 6:14 am
Actually had to look back, purchased her in 2005, time has flown by...
Update? My 30 Pict3 is sensitive to crap in the carburetor. Everything is perfect, but the low-end hesitation is noticeable until I clean it out but good.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 206,865 miles
Naranja - 77 Westy . . . 132,040 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 94,225 miles

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