33 year old choke

[Bonnewagon]

FIXED!! Well, it was cold, but I yanked the carb and damned if the stupid fast idle cam itself was cockeyed! So much that the throttle finger missed it most of the time. The cam is mounted on the choke shaft that goes through the housing into the carb. It could wobble around and was not even contacting the fast idle finger thingie. I have a jar of very thin stainless washers I found at a yard sale many years ago. Two fit on the shaft perfectly between the cam and housing, , removed the sloppiness, and now the cam rides straight as it should. I also put in the seal that seals the housing from outside air on a hot air choke but is missing on an electric model. I figured anything to stabilize the shaft would help. Now the cam is lined up right and engages the throttle finger every time. What puzzles me is why it was so loose and sloppy. And this only happened when it got really cold. On some other housings the cams were pretty much as loose, but not wobbly. Sorry for the out of focus pic, but you can see the light colored finger is above the dark cam, missed completely.

 

[techg8]

well done! glad you got it sorted out!

The fast idle cam should be riding on a pivot or tower extension off the back of the aluminum choke housing. The green choke shaft should pass through the middle of that pivot tower.

If for some reason the extension broke off the aluminum housing, and the fast idle cam was pivoting only on the green shaft, then yes there would be a ton of play and possible misalignment.

 

[olds307 and 403]

I was right :lol:.

 

[Bonnewagon]

Yes you were 307/403! But it took removing the carb to verify that. The extension that the cam rides on was intact, but maybe was worn down? I looked at several other housings I had and they all seemed to be the same but I'll admit I didn't mike them up to see if there was a big difference in size. Plus I wanted to use the '80 electric housing so adding some washers was a cheap and easy solution. Ken, I was almost tempted to use that beautiful carb you built me, but I slapped myself back into reality. This car sits outdoors and the elements would have deteriorated it quickly it would have been sacrilegious. So I am saving that beauty for the TA project that is stalled right now thank's to family problems. I'm still puzzled why it got so sloppy so fast though.

 

[olds307 and 403]

I did the same thing 20 years ago. I tried adjusting the choke coil tighter, it bent the linkage. I actually should have adjusted the pull off tighter to prevent the car from stalling 😳. Led to years of the carb not working right, till I got a free replacement. The Qjet's excellent choke makes it one of few carbed vehicles I would even consider driving in winter. Mine gets parked in October but would function fine with a factory air cleaner and heat tube in -40 temps.

 

[techg8]

Just an FYI, not to hijack but I also have a TA project going on - check it out
http://www.firebirdnation.com/forums/to ... 3-buildup/

but back to the choke discussion.....

Is it possible the cast idle cam developed a crack that loosened it up?

 

[Bonnewagon]

Nope. In fact I couldn't find any difference among all my spare parts. I even changed them around and some fit better than others, but this one stayed sloppy with the biggest gap between the cam and the housing. That's why I just shimmed it so the original parts worked and called it a day. This way it stays an original '80 TA carb, not a mutt.

 

[truracer20]

FIXED!! Well, it was cold, but I yanked the carb and damned if the stupid fast idle cam itself was cockeyed! So much that the throttle finger missed it most of the time. The cam is mounted on the choke shaft that goes through the housing into the carb. It could wobble around and was not even contacting the fast idle finger thingie. I have a jar of very thin stainless washers I found at a yard sale many years ago. Two fit on the shaft perfectly between the cam and housing, , removed the sloppiness, and now the cam rides straight as it should. I also put in the seal that seals the housing from outside air on a hot air choke but is missing on an electric model. I figured anything to stabilize the shaft would help. Now the cam is lined up right and engages the throttle finger every time. What puzzles me is why it was so loose and sloppy. And this only happened when it got really cold. On some other housings the cams were pretty much as loose, but not wobbly. Sorry for the out of focus pic, but you can see the light colored finger is above the dark cam, missed completely

The electric choke coil needs air to keep it from overheating and burning up, whereas the hot air choke needs to retain heat to work effectively. I would remove the seal.