I have a low mileage mostly original 1971 LT-1. Engine is in great shape and I still have the original intake and Holley list 4801 carb. A few weeks ago, I noticed after shut-off, fuel had collected on the intake manifold under each side of the carb. I fired up the engine, shut it down and discovered fuel dripping from both primary and secondary boosters onto the throttle blades, eventually the fuel exited the carb via the primary and secondary throttle shafts. I opened each site plug, inserted an angled pick tool to discover that most/all of the fuel had drained from each float bowl.
I took the carb to a friend that restores Holley's. We went through it together, everything looked fine. Needle/seat, power valve, accelerator pump and shooter all good. Now the carb has new gaskets. The leaking condition through the boosters is still the same.
When we disassembled the carb, we noticed that the metering block gaskets were "wet" with fuel. Another observation I have made is that the fuel drip from the booster does not occur until long after the engine is shut down when the motor is no longer warm. As an example, I drove the car 2 days ago and the engine ran perfect. An hour or two after shut off, no leaking fuel at all. But the following morning I checked and there was fuel on the intake, the fuel leaked out overnight when the motor was cold.
I am not sure what to check next. Is it possible that after all of the years/heat cycles both the primary and secondary portions of the throttle body are warped? Or possibly the same condition on each of the metering blocks? I am wondering if at operating temperature there is expansion that cures the leak but with cold engine the expansion goes away and fuel is passing through the booster feeds internally?
Any thoughts would be welcome. Including verifying the proper metering blocks for my List 4801. Thank you.
I took the carb to a friend that restores Holley's. We went through it together, everything looked fine. Needle/seat, power valve, accelerator pump and shooter all good. Now the carb has new gaskets. The leaking condition through the boosters is still the same.
When we disassembled the carb, we noticed that the metering block gaskets were "wet" with fuel. Another observation I have made is that the fuel drip from the booster does not occur until long after the engine is shut down when the motor is no longer warm. As an example, I drove the car 2 days ago and the engine ran perfect. An hour or two after shut off, no leaking fuel at all. But the following morning I checked and there was fuel on the intake, the fuel leaked out overnight when the motor was cold.
I am not sure what to check next. Is it possible that after all of the years/heat cycles both the primary and secondary portions of the throttle body are warped? Or possibly the same condition on each of the metering blocks? I am wondering if at operating temperature there is expansion that cures the leak but with cold engine the expansion goes away and fuel is passing through the booster feeds internally?
Any thoughts would be welcome. Including verifying the proper metering blocks for my List 4801. Thank you.
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