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Hard to pull choke

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Hard to pull choke
#1
  This topic is about my 1967 Austin-Healey 3000 BJ8
Fautz Avatar
Fautz Silver Member John Fautz
Grass Valley, CA, USA   USA
Are BJ8 Healey chokes normaly hard to pull. It takes both hands to pull mine out fare enough to engage the jets. Any suggestions?

Thank you,
John

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NaDaDawgRacer John Jones
Waxhaw, NC, USA   USA
Seems rather minor but I have found that the outer spiral shield quite often gets bent right where it fits into the bracket on the firewall. This happens normally when removing the valve cover. A kink in the outer shield will drag on the actual inner cable.
John

RTaillieu Rick Taillieu
Leamington, ON, Canada   CAN
This may sound silly but are you rotating the knob CCW to to the unlock position before pulling the choke?

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Montview Silver Member Ronald Keysor
Fleming Island, FL, USA   USA
I don't necessarily recommend it, but I gave up on the choke pull on my BN7 and mounted an off-the-shelf version from one of the auto supply houses. I kept it directly in line with the hole in the firewall and mounted it right beside the steering column but under the dash. The C-marked choke that came on my BN7 remains where it was when it came to me, pretty much centered in the top of the dash, but with the carb end's wire and casing rolled up and tucked away under the dash. I have a lot of experience with bike cables, but I couldn't get mine to pull out without a lot of effort. Further to that, my car is in the serial number range that came with the automatic choke that Healey tried briefly. This is confirmed by the (now blocked) ports in the intake manifold that were employed with that choke system.That suggests that the choke knob, which looks original, was added to the car later.

Fautz Avatar
Fautz Silver Member John Fautz
Grass Valley, CA, USA   USA
That sounds logical. Can the cable be persuaded back to it's original position? I guess I'll discover that myself in a few minutes.
Thanks John.

RAC68 Avatar
RAC68 Raymond Carbone
NJ, Jersey Shore, USA   USA
Hi John,

The simple answer to your question is "YES" pulling the choke knob is a BEAR.

There are a number of issues that cause the hard pull including the way the arrangement of the carburetor's choke return spring. My BJ8 Phase 1 came with a single very strong return spring connected to both chokes through a "Y" wire. Since this pull is not a direct pull, the spring must be strong enough to return the chokes and dash pull by pulling this wire on an angle to both springs (spring force is being applied through the Hypotenuse of both to pull down). Later BJ8s used 2 long springs, each pulling on the chokes of each carburetor. Although the single spring approach could apply less force to withdraw each single choke, it stills requires substantial force to draw from attachment to the superstructure.

To make my choke more manageable to set and withdrawn, I have eliminated my single strong spring and replace it with 2 separate smaller springs designed to push rather then pull. However, differing from the Phase 2 setup, these springs were placed between the upper bracket and choke arm surround the choke cable as depicted in the drawing. When setting the choke, these light springs are compressed and when releasing the choke, these springs assist by expanding. Since these springs are much lighter, the effort required to set and release the chokes is much less.

Since the condition of each set of HD8s can differ, I went to the local home depot and selected variety pack of small diameter springs and tried a number until I found a set that would fully release the chokes consistently. Although excessive force (my opinion) is still needed over what I have experienced in other British cars, I have found a significant reduction in effort over the original setup.
Here is the suggestion I was given when posing the same question.

Hope this helps,
Ray(64BJ8P1)



Edited 2 time(s). Last edit at 2018-02-03 04:10 PM by RAC68.


Attachments:
chkreturn.jpg    32.4 KB
chkreturn.jpg

petnatcar Avatar
petnatcar Silver Member Peter Carbone
Watertown, NY, USA   USA
John,

I have seen one of the strands of the inner cable become detached and start unraveling
inside the outer housing causing the cable to drag.

I'd replace the dash mounted control, lubricate the cables going to the carbs and
see about adding extra springs to those choke levers on the bottom of the carbs like Ray had mentioned.

That's what I did and everything is working smoothly now.

You know there is a locking device on the choke knob, right?

Be sure you're not pulling against the lock!

Good luck,
Peter Carbone

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Rob Glasgow Avatar
Lompoc, CA, USA   USA
Peter, I've owned my BT7 for over 50 years and I did not know the choke had a locking device. I've turned the knob left and right after pulling out the knob and nothing seems to lock. I always have had to hold the knob out when starting the car and until in warmed up a bit.
How is it supposed to work?

rusty1c Avatar
rusty1c Peter D
Antioch, CA, USA   USA
1961 Austin-Healey 3000 BT7 "RUBY"
1963 Chevrolet C10 "Rusty"
John,
As Peter mentioned, sometimes the inner cable will start to unravel which will cause it to become difficult to pull out. However I believe the original inner cable was originally a solid piece and not stranded. If you still have the original solid type, you can tell by looking at the end where it attaches to the carb linkage, it can be freed up considerably by spraying a small amount of spray lubricant onto the outer spiral sheathing along the entire length. I took mine apart and found the inner portion had rusted and that's what was causing the problem. I cleaned the inner portion with a Scotch-Brite pad and sprayed a good rust dissolver lube inside the outer sheath. I reinserted the inter portion of the cable and worked it back and forth. Remove it after a few cycles and wipe it clean. Repeat until the inner cable comes clean of rust.The lubricant will seep into the inner portion of the cable and it will help it considerably.
I also found that by pressing down slightly on the accelerator when pulling out the choke cable helps it considerably as you are not pulling against the accelerator linkage since this also moves and brings the linkage to the fast idle position.
The whole cleaning and freeing up process work better if the entire cable is removed from the vehicle.

Peter,
Rusty1c

Note: WD-40 works OK as a lubricant but doesn't dissolve rust very well, I suggest Rust Blaster or ZEP to dissolve / loosen the rust.

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NaDaDawgRacer John Jones
Waxhaw, NC, USA   USA
Earlier cars, I know up to MkI’s had the solid inner cables and I bet BT7’s were solid as well. The routing of the cable was much more straight. On the BJ8 the cable was moved over toward the center more and it came thru the firewall directly over the valve cover then attached to the two individual cables for each carb. I bet this lead to the stranded cable for flexibility. BUT over the years this cable can end up with a lot of gunk on it adding to the hard pull. The problem with the stranded cable is once the detent bolt is tightened to hold it in place the ends splay out making it very difficult to reinstall.
John

RAC68 Avatar
RAC68 Raymond Carbone
NJ, Jersey Shore, USA   USA
Hi All,

Although everything said can apply, for the greater number of Healey owners experiencing hard pulls of their choke, I still come down to the overkill induced by the heavy return springs installed to guaranty choke closing. Yes, if the spring is insufficiently strong, the choke on one or more carburetors can remain partially set and, through believed off, proper adjustment and performance is lost. However, I have found a lighter spring applied directly to each choke (as presented in my last post) can diminish needed setting force and still provide a secure choke reset. How strong the spring should be on each carburetor is left for experimentation but can easily be determined.

Yes, a fraying cable can drag on the cable sheath and present resistance and yes dirt and grime can also do the same. However, these conditions can easily be identified (though the cable will need to be dismantled). It is when this has been determined to not be the cause of choke-set resistance and substantial effort is still needed that spring evaluation and replacements should be considered.

Just my thoughts,
Ray(64BJ8P1)

petnatcar Avatar
petnatcar Silver Member Peter Carbone
Watertown, NY, USA   USA
John,

If you leave a long enough tail on the stranded cable it shouldn't be able to unwind past the pinch point.

Seems as though I had good luck soldering the ends of the cables then sanding down to the wire diameter.

Stainless steel wire may give you a little problem.

Regarding the return springs:

I'd prefer a stronger spring so I'll always know the choke is off.

When I release the choke it literally snaps back into the dash.

Be absolutely sure to mount the choke springs so they pull straight down on the Jet Hand Control Lever (Choke Lever) without any sideways stress.

Good luck,
Peter

Fautz Avatar
Fautz Silver Member John Fautz
Grass Valley, CA, USA   USA
Hello again,

Thank you all for confirming that BJ8 chokes are difficult to pull. A lot of good suggestions,
however I've recently discovered the front carburetor's choke "cam shoe & rod" (the little brass cylinder that seems to acts like an accelerator pump on the left side of the carburetors) is a rough when activated. I'm sure that's adding to my problem. I'll need to remove the carb and investigate further. (Oh no, not again)

My choke knob won't lock in either direction. Did they make some that didn't lock? Is there any way to make mine lock when rotated without replacing it?

Thanks for your ideas,
John

RAC68 Avatar
RAC68 Raymond Carbone
NJ, Jersey Shore, USA   USA
Hi John,

The best description and explanation of the BJ8's choke operation and locking mechanism was written by Michael Salter (http://www.netbug.net/blogmichael/2007/01/17/bj8-choke-woes/) a while back and I only recently rediscovered it.

Take a look and I expect it will provide many answers. To check the presence of the locking function, make sure your pull knob shaft has a groove and the spring band still retains the ball bearing.

All the best,
Ray(64BJ8P1)



Edited 2 time(s). Last edit at 2018-02-10 09:03 AM by RAC68.

Rob Glasgow Avatar
Lompoc, CA, USA   USA
Ray, thanks for the link. I explains the locking mechanism brilliantly. I'll check my car when I get home to see if there is groove in the shaft. I don't recall seeing one, but maybe it's there.

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