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TR2/3/3A TR3 choke question

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NutmegCT

NutmegCT

Great Pumpkin
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New owner choke questions:

I read in the manual that when the engine is started cold, pull the choke all the way out, switch on the ignition, then press the starter switch button. Then "when the engine has warmed up, turn the choke control and allow it to return to the half-out position and turn to lock in this position. When the engine is sufficiently hot to run without undue hesitation, push the control fully home."

When I pull the choke knob out (goes about an inch), it tries to pull itself back in, to about 1/4 inch from the dash.

I can't feel or see any "half lock" point.

When I cold start the car, am I supposed to *hold* the choke all the way out and keep holding it until releasing and locking to that "half lock" point I don't seem to have? And should there be a natural "half lock" point in the mechanism somewhere?

Thanks.
Tom
 
A new one works that way. When mine failed to engage the "step" to hold itself out, I used the "old clothes-peg" trick. Pull it out, put the peg around the shaft between the know and the dash and start the car with both hands free. In 1953 to 1963, these cars were designed and built to be everyday cars, winter and summer, cold and hot, misty drizzle etc. In the summer, they are rarely needed. I only drive in the summer.

I start my TR3A with the choke, but as soon as I'm on the road a few second later, I push in the choke. If I come to a stop or a traffic light, I ether rev the engine or pull the choke (or both) just before it stalls.
 
There are five notches in the choke cable mechanism that will lock it into any one of those five postions, plus all the way off. If you pull the knob all the way out (about 2"-2 1/2"), you should see some of the notches. Depending on how the cable is orientated, the notches may be underneath. There should be a sharp edge on the back end of the notch, and a slope on the front end.

The sharp edge is what hold the choke cable a out against the spring loaded gizmo inside the sheath. To disengage, you have to twist the knob 90 deg clockwise and push in.

If you need a pic, I'll take one. I've got an old cable down in the basement. I'll dig it out.

It's possible your cable was man handled. Not too many owners know about twisting the cable to release it, and jam it forward, messing up the sharp edge on the notches.
 
Don and Art - that is very interesting. My cable only pulls out 7/8 or 1 inch *total*. And there are definitely no notches in the part that's viewable between knob and dash.

Is there a guide to adjusting the choke cable mechanism?

Edit 7:30pm EST - I found some excellent pictures Harry Ward put in a thread back in early February:

https://www.britishcarforum.com/bcforum/ubbthreads.php/ubb/showflat/Number/249817/page/0/fpart/1

Comparing my linkage to Harry's, my choke cable is kinked, and only moves the jet lever about 1/4 inch. I'll do some adjusting there tomorrow morning.

Thanks.
Tom
 
Here's a pic of the choke cable. It's pulled out so the last notch in the cable is in the locked position. As you can see, there are three of the five notches clearly visible.

The distance between the ferrule on the sheath that butts up against the dash and the back of the knob (not the end that the printing is on) is a little more then 2 1/4".
 
Art - your cable picture is worth a thousand words. Mine won't even pull out enough to get to that first notch, much less the others farther down the line.

I've got some serious adjusting to do.

Thanks.
Tom
 
Got one suggesttion ....pull really hard! It takes more force that you expect to actually lower the jets. OK, make that 2 suggestions. Also, check the connection of the jet arm to shaft fork. Make sure he arm is engine side of the fork and not in the fork, Makes a big difference.
 
Ed,

I am not sure what you meant by your statement

"Also, check the connection of the jet arm to shaft fork. Make sure he arm is engine side of the fork and not in the fork..."
I want to check my linkage tonight to make sure it is correct,

On my car there is an arm that pivots the jet downward, so how should this be connected to the fork on the linkage?

Thanks,

Tim
 
My recollection is that the idea of the 'full out' then 'half out' procedure is that in the ideal set-up having the choke half-out only opens the butterfly a bit with full-out being the position that also lowers the jet.

The connection of the front of the choke linkage to the jet arm is so counter-intuitive that it is usually done wrong.

Common sense tells you that the fork end should surround the the eyelet on the end of the jet arm... whereas I've been told that the fork should really be to one side of the jet arm. Supposedly the linkage will bind if not set up this way but I have not really noticed that it matters much on mine. Perhaps the connections on mine are so worn that binding isn't likely.
 
Yes, well mine is set up so that the tines of the fork straddle the arm eyelet. According to what you are describing this is wrong although as you state it is opposite to common sense...

I will try this new setup tonight. Now, does the cable go on the engine side or outside of this setup? (I believe that it can be installed either way).
 
Adding another facet to this: the choke knob is *really* tough to pull out. With all my strength I can just get it out about a half inch. I also notice a lot of "wiggle" in the jet arm linkage parts; lots of pins through holes that aren't "tight" - but I don't know if that linkage is supposed to be tight (no wiggle) or not.

However, if I disconnect the two return springs on the jet arm linkage, the choke pulls out almost two inches with very little resistance. Of course, it doesn't return without the pull of the springs I disconnected.

Are those springs supposed to make the choke operate so incredibly difficult? Even with only one spring attached, the choke is still just as tough to pull out. They only have to stretch about 1/4 inch to hook under the top of the linkage, but it's *really* tough to pull the choke with even one spring attached.

Thanks.
Tom
 
RedTR3 said:
Yes, well mine is set up so that the tines of the fork straddle the arm eyelet. According to what you are describing this is wrong although as you state it is opposite to common sense...

I will try this new setup tonight. Now, does the cable go on the engine side or outside of this setup? (I believe that it can be installed either way).
Click to expand...

The diagram in my Haynes as well as the one in my Triumph TR2/3 Service Instruction Manual shows the "choke cable swivel pin" on the engine side of the jet lever.

Edit: I did notice however that if the fork of the connecting rod goes "around" the jet lever, the fork interferes with the choke cable going fully back. So I moved the fork to be fully on the outside (fender side) of the jet lever.

Tom
 
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