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TR2/3/3A TR3 choke cable driving me crazy!

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jdubois

jdubois

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/bcforum/images/%%GRAEMLIN_URL%%/mad.gif /bcforum/images/%%GRAEMLIN_URL%%/mad.gif /bcforum/images/%%GRAEMLIN_URL%%/mad.gif This thing is driving me nuts. I can't get the choke cable to operate correctly on my '60 TR3A. I've just been running the car with no choke, but it's really tough to get started when cold, obviously.

I can operate the chokes easily with the choke cable disconnected by pushing on the jet connecting rod right where the cable is supposed to connect, and I can easily move the choke cable back and forth when it's not connected. But when I connect the choke cable to the attachment bolt and try to operate it from the dash, it won't budge more than a tiny bit. To the point that I just broke the choke cable trying!

Anybody have any experience to impart while I wait for the new choke cable, so I don't just break that one too?
 
One thing to know is that you never want to withdraw the cable any farther out than you would in normal operation. There is a little moon shaped piece of metal (about 3/16" by 1/16", curved on one side) that is trapped in there under that clip/band around the shaft at the knob end.

That piece is what holds the cable at each of the notches as you pull it out (rotating the cable allows it to go back in). If you pull the cable too far out (to the point where the thick part of the shaft is withdrawn) there is nothing holding that little metal piece in place and it can fall into the housing or to the floor.

The other thing to be sure of is that everything is nicely alligned between the clamp that holds the cable housing under the carb and the arm that the inner cable clamps to. A bend here can cause binding.

Finally, the whole arrangement of the linkage is somewhat counter intuitive.

Here's a pic (previously posted by someone) form the 'Practical Hints' book. As it shows, the front of the carb-to-carb linkage straddles the jet lever but the rear lever is to the outside of the U-fitting. Anyway, gives you an idea of how it should look:



Carb%20Linkage.jpg
 
Ah! Thank you, Geo! That may indeed have been at least a lot of the issue. The rear level was not on the outside of the U-fitting as you describe (and the picture shows) but straddling it like the front one.
 
Jay,

Welcome to the forum. Are you anywhere near RI?

Please see PM that I sent you as well.
 
Thanks for the welcome! I've been mostly lurking for the last six months or so. Sold my Spitfire a bit ago, and have been concentrating on fixing my other car (don't know if F*rr**i is a dirty word around here /bcforum/images/%%GRAEMLIN_URL%%/wink.gif ) but now I'm trying to get my TR3 into shape. I'm not really that close to RI anymore, used to be, but I'm closer to NH now.
 
Jay - did you get that choke to work easily? I spent time over six months dealing with exactly what you described. Now mine works smooth as silk.

If you still need help, let us know. I'll post the steps I took.

First test: when you try to lower the jets by hand, how hard to you have to push/pull that lowering arm? Remember they only need to come down about 1/2 inch or so, and be sure the fast idle cam linkage isn't causing any binding. The first 1/2 inch or so of cable movement shouldn't lower the jets at all - it should only actuate the fast idle cam.

Tom
 
Hi Tom,

Thanks for jumping into the thread. I haven't received the new choke cable yet, so haven't had a chance to check the operation again. It's definitely not binding of the jets or the fast idle cam, that all moves smoothly and easily when operated by hand.

But I have now found two things wrong with the geometry of the setup, thanks to Geo's picture. First, the choke cable attachment bolt was the wrong way around, so that the choke cable was getting attached on the fender side of the linkage instead of the engine side. Second, the rear U-connector of the jet connecting rod was straddling the rear jet lever instead of being attached to the inside (engine side) of the lever.

I'm hopeful having those two things corrected, and a new choke cable installed, will solve my issue. Otherwise, I'll be back complaining some more. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
The choke cable is pretty wimpy; what feels 'easy' to your hands may well stymie the cable.

When I bought TS39781LO back in 84, the jets were just a little bit stiff, but the dash knob wouldn't move them at all. Neither the owner nor the seller seemed to understand what was going on, and the car was advertised as "not running". The seller was totally amazed when I opened the hood, grabbed the choke lever with one hand and pushed the solenoid button with the other ... it roared right into life. I drove it home with the silliest grin on my face ... still the best birthday present I've ever gotten.

Anyway, if you put new return springs on the jets, they should be plenty strong enough to pull the jet back up against the mixture nut. If they don't do that, likely someone has stretched the gland spring inside the jet housing, and it should be replaced. Also, the surface of the jets should be polished. If yours are dull, polish them up with toothpaste or similar.

After all that, my knob still takes plenty of force to pull.
 
Just adding to Randall's suggestions - I did lots of straightening, re-placing the linkage, polishing the jets, lubing them with vaseline, replacing the seals, recentering the jets, etc.

The thing that finally got my choke cable working easily was replacing a bent fuel jet. That thing was nearly impossible to slide inside the carb, but only at a certain point; otherwise it slid easily. Can't for the life of me figure out how a jet could get bent, but I placed it on a straight edge and found it actually rocked like a miniature brass cradle. Oy.

Tom
 
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