Light bucking at steady speeds under 45mph

[TheRetroBug66]

For the past few days I’ve been pulling my hair out trying to figure out why my car is bucking at steady speeds and light throttle. The car idles fine accelerates fine and once I get past 45mph will cruise just fine. I have eliminated any potential vacuum leaks, reset the carb settings, got the points gap and dwell set right and checked spark plug gap. Last valve adjustment was a little over 1,000 miles ago. This is driving me nuts. It’s my daily driver so I need to get it sorted fairly quickly.

[glutamodo]

One possibility that I have had happen to me in my 62 Bug, is the front mount of the transaxle went bad. This causes the entire drivetrain to pivot slightly on the rear rubber mounts. This pivot or tilt action causes the angle of the fan shroud to change compared to the frame, so the tension on the throttle cable changes, this alters the speed of the engine, which alters the RPM and torque of the engine, this alters the pivot angle, which alters the RPM. I remember being most noticeable/annoying when I would slow down to 20MPH School Zones in 2nd gear.
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Andy T.

"What is Glutamodo, Horror of Toyko, besides total, fiendish, quality-a-you brain!"

[rcooled]

Replace the condenser.
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'63 Ragtop (current)
'65 Ghia coupe (totaled)
'67 Ghia convertible (current)
'69.5 Ghia convertible and
'62, '63, '65, '69 Bugs (all long gone)

[TheRetroBug66]

Checked for any mounts causing weird throttle blips and put new points, condenser, plugs and wires as well as pulling the carb off to blow through any idle jets. When pulling the plugs i noticed they all looked leak hence why I pulled the carb to clean it. Put it back on and still no change. Started spraying starting fluid to double check for vacuum leaks and the only thing I found was when I sprayed it on the alternator side around the area of the throttle shaft and accelerator pump the engine would rev. This is a fairly new aftermarket carb or at least appears that way given how shiny it still is. Can these newer carbs really wear out throttle shafts that quickly? Been daily driving it for the past 9 months with a 3 month gap when I parked it over the winter. Previous owner told me they hardly drive it since they did the restoration a few years ago. I’m ready to rip it off and throw duals on but I would also like to better understand these 34pict3 carbs and am too stubborn to throw in the towel yet.

[rcooled]

What type of distributor is on your motor?

[scrivyscriv]

[TheRetroBug66]

After putting in ANOTHER set of points and condenser it still made no change other than I could tell the spark was stronger. Went back and just doused the whole engine in starting fluid and finally found a tiny pinhole leak on the right intake boot. It had just barely slipped off to have the smallest pinhole of a leak. Slid it back on retimed and reset the carb and it runs great now. Hallelujah! Not sure how I missed it when first checking for leaks but I don’t care now that it’s fixed.

[ppilotmike]

thank you for posting the repair that fixed it, very helpful!!

[wayne1230cars]

Glad you got it figured out and thanks for posting that. Very helpful to others who may experience this issue.
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1960 beetle
1970 beetle convertible