I have a 600 cfm Holley 4 barrel with electric choke. The choke fuctions correctly, but the fast idle cam won't kick off when I kick the throttle. I have to push it down with my finger and it comes off. Is there another adjustment on these I should look at? Everything is clean and lubricated I don't see why it's sticking. Thanks!
When the throttle is opened just a bit, the wieght should pull the fast idle cam down. It not, something is binding it or the throttle hasnt released it yet.
I have seen the fast idle cams with the weight broken off. If that is not the case hold the throttle open and move the cam by hand. It should move freely and fall to the lowest position when released. Check the steps on the cam for burrs and the screw for adjustment. A slight amount of lube might help, but normally not required. Use something light, like a spray silicone, so it will not gum up. good luck,
I can't visualize the exact choke linkage for this carb, but I'd start by trying to find the fast idle cam. With the choke open, it should pivot freely. Maybe it's supposed to be attached with a shoulder screw so it can't be overtightened, but maybe someone's used a regular screw and caused it to bind up. Maybe a spacer or washer missing somewhere. There's probably a rod that connects the choke valve to the fast idle cam. Some carbs might allow you to install this rod backwards or upside down. It might fit together OK but stll not allow for full, free travel of the lever, cam or linkage rod. Any chance of interference with the intake manifold or base gasket?
I got one that does that, too. but I have another that's OK. and I can't see the difference between the two. I tried enough and have given up. I release it manually, too.
Isn't the fast idle screw under the choke assy. on these? Been a while since I fooled with one. If so, maybe it needs some attention instead of the idle screw.
You have linkage binding or sticking , as mentioned. If it moves by hand and not by itself, it is sticking! Find the bind or cause of the sticking. It should show itself under close inspection. That part should be “ rattle “ loose! I prefer manual as most of the time a properly set automatic choke is bothersome! Bones
Don't know what you used for lube, but that fast idle cam should be a dry fit. Lube can attract dirt and cause problems.
The fast idle cam can break (somewhere close to the line in the picture) and the weighted part falls away so the fast idle speed doesn't drop off when it should. Also they should be dry, not lubed. Lube attracts dirt that can cause it to stick.
If none of these fixes work, you may consider calling Holley. I have found them to very helpful when I had problems.
That's quite likely, but 50sboy asked how to fix the problem yesterday. Now he has more information than was here before.
is the part in the picture upside down., i think it is.im refitting a electric choke to a demon 625 4 barrell vc at the moment very similar to holley.with the choke off you can easily install it incorrectly.im no expert but learning.this evening i had a go.i know how to adjust the flap.its opening and closing.ok but fast idle isnt sorted.if the bimetal element opens and closes the flap the linkage must link to the fast idle.with the red fast idle cam turned upside down doesnt the linkge fit under the fast idle cam in the dogleg at the weighted end and alter the idle speed. tonight i had the linkage over the red cam this must have been wrong tomorrow ill have another try with the link under/ in the dogleg in the cam..i hope im right.ps one vid advised backing of the idle adjustment to make assembly easier.
Yes the picture was upside down. I stole it off the internet and that's the way it was. Sorry for the confusion. Now it's right side up.
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