Hard Start Starting
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Hard Start Starting
1972 Ford 360ci rebuilt stock around 2018.
Holley carburetor, Pertronix distributor\coil and headers. Very simple setup.
I have several Holley’s, the one with the issue is List 4548 450cfm - 4160. This carb makes the truck run great. Snappy no bogs no issues while running tuned perfectly for that truck.
The Holley that’s currently installed is a 600cfm 4160 with 4150 center float bowls. This carb also runs good, but the 450cfm seems to have slight edge on performance. So I’d prefer to run the 450.
Here’s the problem: when the 450cfm is installed the engine is nearly impossible to start, 20 30 40 seconds of cranking the motor over until finally, it will barely start then pickup running.
Without changing anything on that motor; other then switching to the 600cfm the truck will then start the moment the key is touched.
What is causing that 450 to be so difficult to start.
Holley carburetor, Pertronix distributor\coil and headers. Very simple setup.
I have several Holley’s, the one with the issue is List 4548 450cfm - 4160. This carb makes the truck run great. Snappy no bogs no issues while running tuned perfectly for that truck.
The Holley that’s currently installed is a 600cfm 4160 with 4150 center float bowls. This carb also runs good, but the 450cfm seems to have slight edge on performance. So I’d prefer to run the 450.
Here’s the problem: when the 450cfm is installed the engine is nearly impossible to start, 20 30 40 seconds of cranking the motor over until finally, it will barely start then pickup running.
Without changing anything on that motor; other then switching to the 600cfm the truck will then start the moment the key is touched.
What is causing that 450 to be so difficult to start.
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Joined: Jul 2017
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From: San Jose, CA
Ditto to both of those checks.
But you can change your tactics as well sometimes. Maybe when the 450 is on, pump the throttle several times first. Like for example, five or six times instead of one or two that you currently do maybe?
See if that makes a difference.
Another thing is, perhaps the 450 is vented so well that the fuel in the bowl evaporates much more quickly than the 600.
You could test that theory by simply putting a little thimble full of fuel down the throat. If it starts instantly, then the next step is to, put some fuel in the float bowl itself the next time.
Dribbling gas into the bowl vent is how you do that.
If that makes the difference, then the 450 is simply losing it overnight.
I guess I should ask first, though, does it do it every time you start? Or just when starting cold?
But you can change your tactics as well sometimes. Maybe when the 450 is on, pump the throttle several times first. Like for example, five or six times instead of one or two that you currently do maybe?
See if that makes a difference.
Another thing is, perhaps the 450 is vented so well that the fuel in the bowl evaporates much more quickly than the 600.
You could test that theory by simply putting a little thimble full of fuel down the throat. If it starts instantly, then the next step is to, put some fuel in the float bowl itself the next time.
Dribbling gas into the bowl vent is how you do that.
If that makes the difference, then the 450 is simply losing it overnight.
I guess I should ask first, though, does it do it every time you start? Or just when starting cold?
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Cross-Country
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The choke lever has been disconnected for many moons.
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The only time this Holley wants to start correctly is first thing in the morning.
After that weather it 30 seconds, 3 minutes or 30 minutes after I shut off the motor - then it's near impossible to restart. And would like to re-iterate, the very moment I put on the 600, the motor starts normally correctly.
After that weather it 30 seconds, 3 minutes or 30 minutes after I shut off the motor - then it's near impossible to restart. And would like to re-iterate, the very moment I put on the 600, the motor starts normally correctly.
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