Vintage Oldsmobiles Curved Dash, Limited Touring, Models 40, 53, 66; Series 60, 70, 90

New Electric Fuel Pump Pushing Gas out of Carb

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Old Apr 23, 2026 | 10:43 AM
  #1  
bobfake's Avatar
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From: Bethany Beach, DE
New Electric Fuel Pump Pushing Gas out of Carb

Hi all,

I just installed a new electric fuel pump on the '27 Olds Landau. The pressure must be too high, as it is pushing gas out of the back of the carburetor. There is no way to decrease the pressure that I can see at the pump, so what are you using to decrease the pressure between the pump and the carburetor? Old pump was an Autopulse 500.

Thanks!!
Bob


Old Apr 23, 2026 | 10:53 AM
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Need a regulator and pressure gauge. Did a '27 have a mechanical fuel pump? I'd think it would be gravity....
Old Apr 23, 2026 | 10:57 AM
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Dollars to donuts a ‘27 had no electric fuel pump. ‘Why’ are you installing an electric fuel pump?
Old Apr 23, 2026 | 11:50 AM
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Replaced an electric Autopulse 500 pump.
Old Apr 23, 2026 | 12:32 PM
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Originally Posted by bobfake
Replaced an electric Autopulse 500 pump.
That's right, you did say it was an Autopulse 500 - I actually wasn't aware that pump was/is electric. A simple question comes to mind though. Is the car's wiring 6VDC or 12VDC? The wiring all look correct? Just a thought.
Old Apr 23, 2026 | 07:39 PM
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A '27 Olds would have had a Vacuum tank on the firewall that gravity fed the carb .
These units are extremely hard to find parts for, and anyone knowledgeable enough to fix one.
That's why they were often replaced by electric fuel pumps.
The fuel pump you have in there now has way too much pressure.
You might try to find an adjustable fuel pressure regulator.
You only need about 1 or 2 PSI at the carb.
Try something like this:
⭐1-6 PSI Universal Adjustable Fuel Pressure Regulator Kit For Carburetor Engine⭐ | eBay
Old Apr 24, 2026 | 04:55 AM
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Wow! You don't run across pre-war Oldsmobiles very often. Good luck getting her back on the road.
Old Apr 24, 2026 | 07:40 AM
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6V. Only difference is the new pump has a negative ground wire versus the Autopulse which grounded directly to the chassis.
Old Apr 24, 2026 | 07:58 AM
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Thanks!!
Old Apr 24, 2026 | 07:58 AM
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Originally Posted by Olds64
Wow! You don't run across pre-war Oldsmobiles very often. Good luck getting her back on the road.
Runs and drives like a dream!! Licensed, insured and driven!!
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