Best Way to set the idle mix on a 4160

steve meltzer · #1 (**permalink**) 10-11-2018, 06:09 AM

OK, the saga continues...drove the car yesterday....ran great, no hiccups, no stalling and no scaring the feces out of me. I didn't have time to recheck the timing, tho' I suspect it's fine. will recheck this weekend, and, if unchanged, will punt on the piston stop, at least for the moment.

Here's something weird that's been going on for several months and could be related, but not sure....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. Other than the same gremlins deployed by me ex, any thoughts? Related to the off idle stumble? Probably hard to tell without the carb in your hands. Next, i was going to put the carb on the bench and check it out, and or, loosen the hold down nuts and see about that. thanx. s

patrickt · #2 (**permalink**) 10-11-2018, 07:14 AM

Quote:

Originally Posted by steve meltzer

Here's something weird that's been going on for several months and could be related, but not sure....

Hmmmm, nothing like an elderly patient that continually presents with new and unusual symptoms.

First thing I would do is give the areas surrounding your primary shaft and linkage a good spray with WD-40, work the linkage back and forth, and then give it another spray. Even on a well-behaving carb, you'd be surprised at how that improves the smoothness of it all. Then see if that has done any good or not.

steve meltzer · #3 (**permalink**) 10-11-2018, 07:34 AM

OK, let me try that before I remove the carb, which I was about to do. thanx. s

steve meltzer · #4 (**permalink**) 10-14-2018, 07:07 AM

Patrick, i drove the car pretty hard on Friday and Saturday, after shooting a bunch of carb cleaner, not WD40 (my usual, defiant self!), on that 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 great thereafter. (BTW, the off idle performance is pretty good...and might be better with the new "red" pump cam, which should be here tomorrow. Timing remains nice and steady at 10° BTDC).

Would taking the carb off the car, and onto the bench help any?? I guess I can just live with it, but I like things to work the way they were intended. thanx s

patrickt · #5 (**permalink**) 10-14-2018, 07:27 AM

Quote:

Originally Posted by steve meltzer

Would taking the carb off the car, and onto the bench help any?? I guess I can just live with it, but I like things to work the way they were intended. thanx s

I think you have to. And here's why, anything that can stick in the "closed" position can get a notion to stick in the "open" position. Short of "off-roading" in your Cobra, the scariest thing I can imagine is a stuck throttle at anything close to WOT conditions. Hopefully you have a rev limiter on your car, so you can throw in the clutch and listen to her bounce of the limiter until you can reach for the key, but it will still be a pretty significant safety hazard. Of course, if you don't have a rev limiter then you'll get the opportunity to chat with blykins about "so how hard is it going to be to fix this window in the side of my block?"