Before I pull this carb... 4180C Holley/Motorcraft
#31
06-11-2021, 03:59 PM
hmm, the choke is closed or 90% closed each morning and stays in that position until the engine is warm, then it opens up. each time I have observed the choke function it has done the same thing (the entire time I have own the truck); slowly opens as the engine gets to operating temperature. does it have another adjustment that effects the idle? I thought it was only richening the mixture by restricting air. I was thinking something I did while 'cleaning' the carb must have effected the idle speed, but with the fuel levels going haywire I considered that as a possible influence on the idle and especially the dying.
Maybe I should have titled this thread 'Before I pull this carb 3 more times!' lol I think I should remove it again and maybe go as far as doing a rebuild but reusing the existing o-rings, seals & diaphragms since they aren't very old at all, that's if they are in ok shape.
Maybe I should have titled this thread 'Before I pull this carb 3 more times!' lol I think I should remove it again and maybe go as far as doing a rebuild but reusing the existing o-rings, seals & diaphragms since they aren't very old at all, that's if they are in ok shape.
The other adjustment is what Dave posted is the fast idle.
It kicks the idle speed up when the choke comes on.
There is a stepped cam that moves with the choke and there might be a fast idle screw that hits this cam.
With out looking at the carb I cant say how yours is set up.
Dave ----
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#32
06-11-2021, 05:54 PM
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#33
06-11-2021, 08:04 PM
You will find some 4180 fast idle cam notes and pics if this link works:
https://www.ford-trucks.com/forums/1...l#post18297824
https://www.ford-trucks.com/forums/1...l#post18297824
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#34
06-13-2021, 09:05 PM
Brnfree, thanks. that was my post from 2018 when I was even less familiar with this carb! lol. Also thought the truck was an '85 for a while back then, hehe. I removed the two idle mixture screw tamper resistant plugs up front and extracted the screws just to make sure the passages were clear, everything looked good and put new o-rings in for good measure. I was about to re-install the carb but watched the youtube video one more time and tried to copy what that fast talking fella was doing and got lost again BUT figured the settings could be close so I turned the fast idle cam screw 1/2 turn in and the idle mixture screws up front 1/4 turn out and the secondary throttle limit screw 1/2 turn in and put it back on the truck. I was already committing to taking it off again to make adjustments from there and I wrote down each of those changes that I made. When it finally had some fuel in the bowls it started pretty normally and the idle was up much higher than previous. Also the choke opened much sooner than previous (it was set per the video before I had given up). It warmed up and moved the temperature gauge a bit so I gave it a few revs and it seemed to respond correctly, then I figured it was good and warm and I turned the curb idle screw in 1/4 turn, twice, and the idle seemed about right. Again revving the RPMs up responded smoothly and came down to where it had been. Putting it in gear the idle lowered and was steady so I need to get it on the road and check drivability. I hated to adjust so much at once but all of those adjustments were mentioned in my 'research'. think I'm gonna end the day on this positive result!
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