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Jmaustin17
Samba Member
Joined: November 15, 2022
Posts: 8
Location: Florida
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 Posted: Fri Jun 13, 2025 2:38 pm Post subject: Low Idle Knocking, Please Help Identify - 1971 Type 3 |
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Hello! Any input is greatly appreciated.
I recently took my 1971 Squareback to my trusted mechanic to do a tune up (Mixture, Idle, Timing) since I do not have the fancy tools to tune my dual carbs. Previous owner switched out the injection for essentially a 1967 setup (Twin solex PDSITs). I have a 009 with electronic ignition which is timed at 10 BTDC. I had it timed at 0 BTDC before that. Car ran great driving back from the mechanic. Did not drive it for a few days after that. I started the car and the gas pedal got jammed at full revs. Somehow the fresh air bellows got sucked into the pulley shroud. right after I turned off the key. Thankfully got it out and repaired the pedal which had corroded. I replaced the bellows and the car ran with no extra noises. I drove the car for 30 minutes and it started to stall and run inconsistently. Pulled over a couple times and it would run again for short periods of time. Made it home with still no extra noise. Was advised that maybe I had bad gas or something wrong in the fuel circuit. I did not start the car again for 8 more hours.
Finally here's the problem. I started the car again that evening and it was idling really low and had a knocking noise. Sounds like its coming from the pulley or fan shroud. I'm at a loss to what this could be. The mechanic from earlier had said I need new carbs and the knock would go away. The knock being a result of poor running. At higher revs the knock is inaudible or goes away. I will attach a video of the knock to this post. I did drive the car to see how it would behave and it runs like a top. I cant hear the knock as I shut the car off hasn't run since.
I know this is a long post but I though it was necessary to explain everything that led up to this issue. The car ran okay before the trip to the mechanic. Not great, but just okay. Took it because I believed it was having problems that I could not diagnose. This is a daily driver car. Engine was rebuild 2.5 years ago and only has 16784 miles. I am at my wits end.
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Max Welton
Samba Member
Joined: May 19, 2003
Posts: 11035
Location: Black Forest, CO
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Jmaustin17
Samba Member
Joined: November 15, 2022
Posts: 8
Location: Florida
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| Posted: Fri Jun 13, 2025 3:54 pm Post subject: Re: Low Idle Knocking, Please Help Identify - 1971 Type 3 |
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| Found it! Definitely was the pulley/fan. Thank you! |
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