Holly 4175 accelerator problem
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Instructor
Joined: Nov 2012
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Holly 4175 accelerator problem
A while back I replaced my Quadra jet with a 4175 holly. It ran well when put on. I also decided to replace the engine wiring harness. It took several months to finish that.Two weeks ago the car cranked and ran. Today no go. Squirted gas in front barrels and fired for a second till gas ran out. So checked gas flow. Gas is flowing through the engine pump. Took filter out of carb and tried, still no gas out of nozzles. Only other thing I can think of is accelerator pump. Took it off looks ok. How far should the lever travel when pumped? It seems to barely move. Don’t understand what could have happened. Help!
Thanks
Fred
Thanks
Fred
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the accelerator pump is what squirts the gas into the front barrels. You probably have sticking needles and seats/ floats. Does your carb have sight windows, so you can see the fuel level. If it started by pouring gas into the carb but it stops running then its not getting gas into the carb or just not through the idle circuit. YOu can try tapping on the front and rear fuel bowls with a screw driver handle and see if it frees them up. If not you may have to pull it apart and rebuild it
Last edited by Rescue Rogers; Oct 24, 2019 at 07:32 AM.
Drifting
Joined: Apr 2017
Posts: 1,377
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From: Bedford New York
First things first. Assuming you have a good amount of gas in your fuel tank; with the engine off and the air cleaner off, look down into the primary side of the carb, and operate the accelerator lever. Do you see gas squirting into the carb? Report back.
Drifting
Joined: Apr 2017
Posts: 1,377
Likes: 282
From: Bedford New York
No gas out of nozzles could mean that your float/float pin is stuck closed. I'd usually also suspect that your fuel pump isn't pumping gas, but I believe you said that you already checked that? If not, disconnect the fuel pipe to the carb, insert it into a coffee can, and have someone crank the engine over for a few revolutions to see if you are getting good flow. Assuming yes, let's open the primary fuel bowl and see if the float pin or the float itself is stuck in the closed position. Report back.
