72 LS 5 performanc
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Intermediate
Joined: Apr 2024
Posts: 40
Likes: 5
72 LS 5 performanc
My 72 LS 5 starts fine idles at 1300 until warm then drops to 600 and will idle easily there. In any gear when I floor it there is hesitation. Engine rebuilt 15 years ago but only 100 miles on it. New fuel pump. Seems to pull ok once the hesitation happens up to 4500. 4500 to 5600 is not as quick as it is getting to 4000. Any ideas?
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,031
Likes: 4,387
From: Marlton NJ
Could be accelerator pump, or a few other things.
Give throttle a long hard push, engine off, while looking down the carb throat. Do you see a strong pump shot?
Do you know the timing curve?
And vac can settings?
Stock cam?
Vac reading at idle?
Give throttle a long hard push, engine off, while looking down the carb throat. Do you see a strong pump shot?
Do you know the timing curve?
And vac can settings?
Stock cam?
Vac reading at idle?
Burning Brakes
Joined: Apr 2020
Posts: 788
Likes: 418
From: Western NY
Also check the choke pull off or vacuum break diaphragm for the secondary air valve. If it’s leaking it will let the air valve open too quickly and create a bog or hesitation when you floor it.
Pat
Pat
