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Here's something weird that's been going on for several months on my '67 327/350 'Vette, Holley 3810. When the car has been sitting overnight (tho' the ambient temp in my garage is in the 90s) the throttle arm is very hard to move initially. Meaning, when you step on the gas pedal, your foot meets immediate resistance, then, with sig. more pressure, it gives way, and the pedal and entire throttle mechanism move well the rest of the time. Disconnecting the linkage from the carb's throttle, or main shaft, arm proves it's in the carb, NOT the linkage to the pedal.
So, when cold, something's binding in/on the carb that "unsticks" once warm. Even driving the car to work, parking and heading home after an 8 hour day does NOT yield this weirdness.
I drove the car pretty hard on Friday and Saturday, after shooting a bunch of carb cleaner, tho' not WD40 on the throttle shaft, and any other part of the carburetor that would hold still, but it made no difference. This AM I really had to put my foot on the pedal to move the throttle, then it "broke loose" and, of course, great thereafter.
I might try loosening the 4 carb to manifold hold down nuts to see if that's binding something, otherwise i'm out of ideas.
Other than the usual gremlins deployed by me ex, any thoughts? Worth removing the carb and putting her on the bench?...tho' not sure what i'd be looking for. thanx. s
LOL! I thought I had a similar problem....After almost tearing my carb apart............Turns out it was the floor mat under the gas peddle...............
Since you disconnected the throttle rod I’m guessing the carpet is not the issue. Sometimes the fast idle setting on the choke can cause this problem. It binds until set and then once the engine warms up the fast idle is disengaged and everything works fine. I would start there by inspecting the fast idle when the engine is cold. Good luck!
thanx guys. I don't think my description was as helpful nor accurate as it should have been...this never happens within 8hrs of being driven. But, even if stone cold, once you stomp the go pedal (or release the throttle arm manually) it releases and you're good to go. Meaning, you could stomp the pedal, not start the car, and come back 3hrs later and you'd be good to go...it would be fully released. argghh and thanx again. s
Yeah, Phil, I thought about the butterflies sticking in the bore, but there are so many moving parts that I wasn't certain. Let me try to sl. loosen the hold down nuts and see if that makes a difference...not hopeful. I had the carb out to fix a needle and seat issue about 4 weeks ago and this problem ANTEDATES that repair. thanx. s
thanx guys. I don't think my description was as helpful nor accurate as it should have been...this never happens within 8hrs of being driven. But, even if stone cold, once you stomp the go pedal (or release the throttle arm manually) it releases and you're good to go. Meaning, you could stomp the pedal, not start the car, and come back 3hrs later and you'd be good to go...it would be fully released. argghh and thanx again. s
Wonder why this would occur out of nowhere? If that's the case, taking the carb out probably wouldn't help much, as the fast idle mechanism can be adjusted on the car. Correct? s
Yeah, all problems seem to come out of nowhere. I wish I could identify half the causes of my issues!
When you are confident that the issue will occur, take the air cleaner off, disconnect the throttle linkage and find the slotted tab on the passenger side of the carb that I circled in red in the picture below. That is the choke fast idle adjustment and the stepped area in front of it are the steps. Inspect it for any binding or if it looks bent in any way. If all looks fine, reach across the carb and while observing the tab, work the throttle. When your problem occurs, did you notice any binding or interference from the fast idle circuit? Better yet, take a picture of it and share.
Hey Factoid, i was thinking the same thing except i was going to recruit my wife to slowly move the pedal...either way, i was going to observe the fast idle cam and go from there. it's going to rain here in Houston over the next few days, so not sure when I'll get to this, but could post a picture this PM of the current state of affairs. Didn't get to drive the car yesterday, as my dogs had squatters' rights and they weren't goin' to budge. So, this AM, it moved fine, but had been manipulated on Saturday after being driven. so, no dice. thanx again. s
Oh, I didn’t realize you are in Houston. Yeah, this rain is out of control! At least the aquifer in San Antonio is fuller than ever and we have no water restrictions.
To reset back to “problem mode”, you will probably have to warm the engine up completely (choke off) and then turn it off and let it cool completely. I like getting the wife to help, but mine has a short fuse and can be difficult to manage!
here's a shot of the fast idle cam...taken with car turned off, but the throttle moves freely and easily. thanx. s
(Mark, stay dry and safe...bad rains in SA, as i hear it) s
Last edited by steve meltzer; 10-16-2018 at 09:50 AM.
Reason: spelling
Steve, is that fine metal dust on the steps? It looks like you can see the wear on the outer edge and interference creating metal dust on the inside. Something you can try given you live in a relatively warm climate. When the engine is cold, adjust fast idle out of the warm up cycle. In other words, move the fast idle adjustment slightly so that it does not engage while remembering where it was set. You will need to feather the throttle when you first start it until it warms up. Once you adjust it out, repeat all the things you did that caused you to experience the problem in the first place. Good luck!
I don't know, I'm following along, I will report findings, but my car is off site at the moment. BTW one carb is original to the car and one is a later service replacement.
Last edited by Brian VH McHale; 10-16-2018 at 10:21 AM.
could be dust or grit...i'll need to look more closely this PM. Not sure when i'll get back to this, but i'll sure try for it soon and will post. thanx again. s
tried to use a magnet to pick up the debris we saw...not clearly metallic...nothing on the magnet. TBarb, i'll check on that, but wouldn't that exhibit a problem all of the time, not jsut from a cold start up? thanx. s
10-14-2018, 10:38 AM
Another Holley 3810 question
