TR2/3/3A tr3 sticky choke

I've looked thru the search and haven't zeroed in on a problem, so I thought I'd turn to my trusty source of all knowledge - the Forum.
A buddy of mine, having rebuilt and reassembled the carbs on his TR3 can't seem to get the choke cable to return smoothly. Pulling the choke out is no problem, but it sticks on return, and he has to manually bring it back. Could it be the return springs? Or is it time to just replace the cable, and be done with it? Does anyone have a photo of the choke adjustment rod in place? The shop manual only shows the parts and not the final assembly.

With thanks
Dave

There has been some prior discussion of sticky chokes, with the consensus opinion that most sticky chokes come from the jets not operating smoothly where they slide up-and-down in the carbs. Remedies include polishing the outside of the jets and lubricating them with silicone grease. The lube was enough to make mine quit sticking.

Dave - this'll get you started:

https://www.britishcarforum.com/bcforum/ubbthreads.php/ubb/showflat/Number/547310

First thing I'd check is to disconnect the cable from the choke assembly, then pull the choke knob to verify the cable isn't binding somewhere (move the cable back and forth).

Still with the cable disconnected, lower each jet by hand, and see if it pushes back up easily. There's a *lot* of reasons it can get bound up: bent needle, tight o-rings, bent jet assembly, etc. I don't think those return springs were ever meant to pull that whole assembly back up if there's any binding to restrain movement.

Anyway, do some checking and let us know what you find. In my case (and what a case it was!), one of the jets was actually bent *and* the needle case was rough enough to prevent sliding.

Tom

My first step would be to pull the jets back out and polish them. Original jets were supplied nicely polished, but the replacements are generally dull, which means they are also rough and hence drag more heavily on the seal. Ordinary toothpaste and your fingers will work to polish them, if you don't have anything better.

If it wasn't done during the rebuild (frequently overlooked), I'd also replace both the choke return springs and the gland springs inside the jet housings. It's very common for people to stretch the gland springs (trying to stop leaks), which also causes too much drag on the jets.

The linkage also goes together kind of funny, here's a factory photo. Note that the front clevis does NOT straddle the lever.

TR3driver said:

...The linkage also goes together kind of funny, here's a factory photo. Note that the front clevis does NOT straddle the lever.

Click to expand...

Nor (if I'm reading the photo right) does the rear fork. A truly bizarre arrangement that either (depending on your point of view) has parts way more complex than needed or fails to take advantage of the parts that are there.

Nevertheless, I assemble by that illustration for mine.

Your buddy does know that you turn the choke knob about 1/3 turn CCW to release it? There is a little moon-shaped piece under a springy collar that engages notches on the shaft beyond the choke knob. The spring can be overcome by pushing the knob but a little turn of the knob should let it return freely.

Good point about the cable, Geo. On some of the aftermarket ones, you may need to turn it farther than 1/3 turn. Mine has no stop (or notches) so you have to turn it back however far you turned it from the free-running position.

Yes, the rear clevis also doesn't straddle the lever.

Sometimes the split pin in the front carbie choke lever snags the loom running along the inner guard. If it eventually penetrates the loom there can be some interesting electrical dramas.

Removing the link rod (item 11 in the pic) helps, as the car will start perfectly from cold on just the front choke.

This halves the struggle pulling the choke cable, and avoids early failure of the pull knob.

Viv.

My thanks to Moseso, Tom(for the link), Randall(brilliant photo), Geo and Viv for providing excellent suggestions, and your experiences with the sticky choke on my friend's 57 TR3.

This now gives us an afternoon of sorting out in the garage, a break from the wives, and a good excuse to drink some beer. Does life get any better?

Cheers mates.