Firm

Hi Guys,
Just took my stock 85 T/A LG4 out for a ride after sitting 3 months (crappy weather) and even after warming it up and driving around for about an hour the idle wouldn't come down lower than about 1500 rpm.

I pulled the air cleaner and noticed that the throttle mechanism on the driver's side of the carb wasn't resting on the idle screw, there was about 1/16" gap between the screw and the stopper on the linkage. If I forced the linkage against the screw by hand the idle comes down to normal, but as soon as I release my hand the throttle moves back and the idle goes up again.

It this as simple as a weak throttle return spring? Or is there something else going on? Sorry, but I am not an expert by any means on these carbs...

Thanks,

sofakingdom

iTrader: (1)

Where is your return spring?

Ideally, it would EXACTLY oppose the cable. In reality, if it's the factory setup, it doesn't... both the cable and the spring pull rearwards. Not a good design. Ends up destroying the parts over the long term.

End result is, the throttle shaft and the carb base plate both wear. The shaft was coated w Teflon originally.

If your carb is in otherwise perfect operating condition, or at least very close, there's a bunch of places that can drill out the base plate and put in bushings; and re-coat the shaft. Sounds like that might be your best bet.

Firm

Hey, I have read about the shaft and base plate wear, but I don't think that's the issue here only because this came on rather suddenly. I last drove the car in November, prior to storage, and if anything the idle was a bit on the low side (maybe 700ish), now rather suddenly it won't come off 1500rpm.

Bow_Tied

iTrader: (1)

Disconnect the throttle cable from the carb and have a feel for it moving/binding in case the cable is fraying or the sheath is deteriorating. With the throttle cable removed, did the throttle on the carb close properly?

Next check to see if the choke is actually coming all the way off when warm.

Eliminate the cheap easy stuff first, right? G/L

Firm

Thanks, I'll do that.

Any tips on the best way to verify that the choke is coming off completely?

NoEmissions84TA

iTrader: (1)

Yes, is the choke plate vertical when warmed up?
Also, look at the opposite side of the carb (choke side). IIRC, there is a stepped cam that operates off the choke. If it is gummed up, then this could be your problem.

Firm

Should the choke plate be 100% vertical? If I recall correctly, it was probably about 85% vertical, but not all the way there.

NoEmissions84TA

iTrader: (1)

Straight up and down - vertical. Something is preventing it from fully opening.

Firm

OK, thanks. I'll take a good look at the choke next time I get a chance to bring the car out and get it heated up.

Firm

Checked it out. Choke plate was/is opening fully, but the high idle cam was getting hung up on the secondary high idle position. Gave it a thorough cleaning with some carb cleaner spray and it's working fine now. Thanks for the help!

Bow_Tied

iTrader: (1)

Awesome, always good when the fix didn't require big money. Thanks for following up.