TR2/3/3A tr3 choke linkage issues

[Jim Lee]

Guys and gals of The British Car Forum,

I am having some frustrating choke linkage issues on my tr3. I have a new choke lever and cable. I do not think I have ever had it right and believe that this has been a long standing issue in my hard to start problems. I have pictures that I am including here that I hope will show you relatively clearly how I am setup. I have the little clamp that holds the cable housing right before the cable itself that goes to the attachment point of the front carb lever as far forward as possible. I think that my main problem is that I am not able to pull back far enough on the levers to allow the engine to start cold. I know I have an unorthodox arrangement at the point where the cable attaches to the front lever. I believe that part of it is original and correct but much of it (like the many washers I have on it) are not.

These pictures are with the choke pulled out as far as it will go. The first thing I did was pull it out too far. Don't want to go there again. Heard me say words I have never said before....hardly ever.

Any help, tips or advice would be much appreciated. Tell me if I need to get better pictures of anything.

Thanks very much,
Jim Lee

 

[Brinkerhoff]

First thing I did was replace your choke cable assy. from a mid 60s MGB ( Moss under 20 bucks) that has a big T handle , twist to lock . My hands aren't huge but I had a hard time getting a good grip on the stock knob. Second thing is the cable should pass straight out of its housing into the grub screw , not on an angle like yours is. Reverse the grub screw or bend the bracket a little. Mine works easily. Good luck, Kevin

 

[Geo Hahn]

I don't think your set up (yokes straddling the arms) is as original. See your Practical Hints manual for a pic of the correct arrangement (or search the archives or maybe Randall will post the pic). That may account for your many washers and the noted bend as the cable approaches the grub screw.

Also, if you once pulled the cable out t0o far you may have lost the little (and I do mean little) half-moon piece that enables the locking function. If yours will not lock when you pull it out (and the release with a twist) then look for that piece on the floorboard or where the cable knob was when it over-extended.

Finally, you may get more choke action if you sort of pre-load the rear arm so all of the slop is out of the linkage between the front and rear.

<span style="font-style: italic">Okay, found a pic. Note how the yokes sit inboard of the arms -- looks goofy and is counter-intuitive, but there it is black on white:</span>

 

[TomMull]

Agree with Kevin (don't know about the MGB cable) on the lead where the cable comes out of the housing, should be straight . I think you can bend the sheet metal bracket.

Looks like the front carb may be chocking more than the rear but hard to tell from the photo. Make sure the jet is not stuck. You should be able to operate the chokes by hand (there is some spring tension) with the cable disconnected and they should pull the jets down equally.

I was looking at my carbs as Geo posted but noticed that it appears that the cable clamp pin may be backward.

Tom

 

[TR3driver]

Here's a link to a higher resolution scan of the above photo:
https://s258.photobucket.com/albums/hh260...TORSLINKAGE.jpg

(Click on the image for an absurdly large view)

BTW there is some disagreement on what exactly that photo shows; I have mine with the nut & hole for the cable on the near side (towards the viewer of the picture), but some have argued it shows the other orientation.

But looking at your photos, Jim, it appears to me that you have plenty of action at the carb jets (which after all is the only place it really matters). If that is not enough to start the car, then I think you have other problems. Rearranging the linkage so the cable is not bent like that will certainly make it easier to operate, but I don't think it's going to help start the car.

Are you sure the float bowls are not draining while it's parked? That's my most common starting problem. Having the valves set too tight, or weak ignition can also cause issues. One of the most frustrating (to me) is glazed plugs, since they can look fine, and run fine, and still be nearly impossible to start.

Weirdest starting problem I've had was with the Pertronix, that simply would not fire the plugs until the instant I <span style="font-weight: bold">let off</span> the starter button. I think now that it was a sign the battery was dying, but it also seems that the Pertronix takes more voltage to operate than my gear-drive starter does.

 

[CJD]

Just went and studied my linkage for a bit. Here are a couple things I see:

1) Your cable clamp bracket is bent...or rather it is not bent. It should have a slight angle away from the engine. This will allow you to remove the washers, which will help take some of the twisting tendency out of the brass arm when you pull the choke.

2) You are not getting the same amount of piston travel downward that I have. Mine goes at least 50% farther down. It appears you will have more travel when you line up the two arms properly so the cable gets full travel.

John

 

[sp53]

I am on the same page Randall is here in that there is enough choke action to start the engine if the plugs are clean to start with. One thing you might want to check is that the chokes shut off completely because if the jet does not return the plugs will foul quickly. This can happen real quick at an idle if the engine is warm and the choke is on. In addition, the distributor plays a big part in keeping the plugs from fouling. If the timing does not advance or actually floats around when you are driving at a constant speed, the gas does not burn well. What is wrong with the SU carbs is often found in the Lucus ignition.
steve

 

[mrv8q]

One of the most frustrating (to me) is glazed plugs, since they can look fine, and run fine, and still be nearly impossible to start.

I've been following this thread w/ interest, as I, too, seem to have cold start issues w/ my TR3. Had the distributor and carbs rebuilt last year, and not that much difference. Spark plugs were all a nice even tan color. Once the car started, it ran like a top for the rest of the day.

Spent the morning checking connections, etc; no hot battery cables, solenoid in engine compartment gave same results. Then I remembered Randall's comment on the sparking plugs. I have a bunch of new plugs stashed; turns out I changed the plugs about 3 years ago. Couple thousand miles since then.

Changing the plugs, (setting the gap to .025), allowed the car to start nearly instantly. Idle, and everything else, spot on. It's about 50º here now, and rainy. I don't think my car ever started so quickly at these temperatures.

Hopefully the rain will quit by tomorrow morning to allow me a nice brisk run out to Rancho Palos Verdes. A tip of the hat to Randall for his thoughts, and check those sparking plugs!