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| choke kick-down screw https://slantsix.org/forum/viewtopic.php?t=52980 |
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| Author: | 75valiant [ Wed Aug 07, 2013 4:42 pm ] |
| Post subject: | choke kick-down screw |
i ain't got one! my 75 valiant was supposed to have one, but it doesn't. according to the books, it's a 1945 holley. i'm talking about the screw ( with spring) that the warm-up cam rests upon. it's summer now, so when it starts it immediately goes to wide open choke. problem is, my accellerator pump is shot so i'm not getting enough fuel. while i have ordered a new kit for the carb (can't get anyone to sell me just the accellerator pump), i'm going to want the choke to work properly this winter. does anyone have the specs for the screw (and spring)? my local yard is pretty well stripped of carbs, so that option isn't working out. |
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| Author: | kxracer728 [ Thu Aug 08, 2013 7:53 am ] |
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If you have a 75' valiant then the carb you have is a holley 1920 from what i know. Unless someone has changed it and put a 1945 on...When you look at the carb you will be able to identify it and see which one it is When you rebuild the carb you might have to take it to ACE hardware or something like that to find a screw and spring to fit it. You will have to cut the springs length to make it work and make sure the spring is big enough not to bind on the screw when adjusting it. I'm not sure the length of the screw needed it's probably 3/4" I'm using a spring from ACE on my 1920 for the fast idle cam because it didn't have one either... |
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| Author: | Reed [ Thu Aug 08, 2013 8:11 am ] |
| Post subject: | Re: choke kick-down screw |
Quote: i ain't got one! my 75 valiant was supposed to have one, but it doesn't. according to the books, it's a 1945 holley. i'm talking about the screw ( with spring) that the warm-up cam rests upon. it's summer now, so when it starts it immediately goes to wide open choke. problem is, my accellerator pump is shot so i'm not getting enough fuel. while i have ordered a new kit for the carb (can't get anyone to sell me just the accellerator pump), i'm going to want the choke to work properly this winter.
It sounds like you are talking about the fast idle speed screw that rests on the fat idle cam that is linked to the choke. However, the fast idle speed screw has nothing to do with the choke opening or closing. The choke opening and closing is controlled primarily by the choke thermostat rod (the rod from the thing in the exhaust manifold) and the choke pulloff diaphragm (the little round thing screwed to the side of the carb with a vacuum hose on it).does anyone have the specs for the screw (and spring)? my local yard is pretty well stripped of carbs, so that option isn't working out. If you are missing the fast idle speed screw the carb will not go to high idle when cold and will drop straight to curb idle. The choke should still operate correctly, you just won't have high idle. If the choke opens all the way immediately upon starting the engine, then you either have a misadjusted choke pulloff or your choke thermostat linkage is disconnected or missing, or both. The choke being open too far will make the motor run lean when cold, which could be why you think your accelerator pump isn't working and your carb is running lean. Can you post some clear pictures of your carburetor? Specifically the fast idle cam and idle screw area and the choke linkage and the choke pull off diaphragm and linkage. |
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| Author: | xjarhead [ Thu Aug 08, 2013 12:17 pm ] |
| Post subject: | Re: choke kick-down screw |
Quote: i ain't got one! my 75 valiant was supposed to have one, but it doesn't. according to the books, it's a 1945 holley. i'm talking about the screw ( with spring) that the warm-up cam rests upon. it's summer now, so when it starts it immediately goes to wide open choke. problem is, my accellerator pump is shot so i'm not getting enough fuel. while i have ordered a new kit for the carb (can't get anyone to sell me just the accellerator pump), i'm going to want the choke to work properly this winter.
Try here next time for carb parts does anyone have the specs for the screw (and spring)? my local yard is pretty well stripped of carbs, so that option isn't working out. https://buy.walkerproducts.com/carburet ... ts/holley/ Dave |
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| Author: | Sean Mallory [ Fri Aug 09, 2013 6:58 am ] |
| Post subject: | |
Did you find the screw and spring? That screw and spring don't appear on the Walker parts list above. I got 1945 laying on my bench if that will help. |
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| Author: | 75valiant [ Fri Aug 09, 2013 7:46 am ] |
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we had a storm wednesday night and i just now got the internet back on. i called it a 1945 because that's what the parts house website says. hope they're correct, because i just had a kit and float delivered from rock auto! sorry, i don't have a camera. someday i'll come into the modern age, but i'm still using the same brick phone i bought 12 years ago. it works great! the screw in question definitely is the one that the fast idle rests on. with the screw missing, i not only don't have fast idle, the choke will flop around because of the way the linkage is made. when cold, the choke works as it should, except that as soon as vacuum hits it, it flies open. what i do to start it is i take a pair of needle nose vice grips (for no particular reason other than it is the right size and weight to hold the choke plate in place long enough for the engine to fire) in position and start the engine. my accellerator pump is not squirting fuel, so i have to have the choke to get it going even in this hot weather. as soon as the engine fires, the vacuum pulls the choke plate open and i remove the pliers, put the air breather cover back on, and hop back in the car. hopefully, i've gotten the right kit and will rebuild the carb this weekend. if not, i'm out about ten bucks for the kit and float. i sincerely appreciate the responses. i'll let you guys know what i find. sean, i may take you up on that. let me first make sure i have the carb i think i do. |
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| Author: | Reed [ Fri Aug 09, 2013 8:00 am ] |
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It sounds like your choke unloader/choke pulloff diaphragm linkage is adjusted to tight. When the engine is cold you should be able to step lightly on the gas pedal and the choke should be fully closed form pressure from the choke thermostat rod. As soon as the engine starts the choke butterfly valve should be pulled open ROUGHLY (not exactly) 1/4 inch by the choke pulloff diaphragm. The choke should then slowly open the rest of the way as the choke thermostat warms up. If the missing fast idle screw is keeping your choke from staying shut or otherwise interfering with the operation of your choke, something is assembled and/or adjusted incorrectly on the carb. Any screw that fits the threads of the hole will work. Go to your local hardware store and get a screw and a washer and spring that will fit. |
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