Choke Cable Problem

[edwardc]

Now that warm weather is here, I've been reassembling my rebuilt engine back in the boat and am about ready to test it.

In reattaching the choke cable to my late-model carb, I noticed that it does not fully close the choke all the way. Numerous posts here have identified a not-fully-closed-choke as a frequent cause of failing to start. And indeed, before the rebuild, my engine was hard to start when cold, consistently requiring 5 tries on the starter before it would catch.

When disconnected from the carb, the cable moves freely over more than enough distance to fully engage the choke. But when hooked up to the choke arm, and clamped in the cable holder on the carb, it stops about 2/3 of the way towards closed. It seems that the angle of the wire as it exits the cable sleeve becomes so great at that point that it binds in the sleeve. Attempting to put more force on the choke control knob simply causes the sleeve to pull out of the clamp on the carb.

I can't believe that no one else has run into this before, and I'm wondering what kind of fixes have been tried. It seems to me that the clamp is simply too close to the choke lever on the carb for a solid-wire cable. Some sort of alternate clamping scheme that holds onto the sleeve at a greater distance from the end should work.

Anybody have any suggestions or tried-and-true solutions?

[ndutton]

Would changing the clamp angle by using a different pair of mounting holes help the angle? There's a radial array on the clamp bracket mount.

credit pallen58 for the image

[edwardc]

I considered that, but it looked like the choke return spring, which attaches to the clamp bracket. would then have too little travel to return the choke to its full-open position.

[ndutton]

As stiff as most choke cables are I'm not sure the spring does much anyway.

[Dave Neptune]

Choke

Edward, for what it is worth, I have the same choke assembly as Niel and no problems.
I have seen on a few occasions that when clamping the outer cable to much has been left out front and the outer cable stops the travel preventing "full choke".

Dave Neptune

[Crash]

I had the same problems too but it took 2 of us and trial and error to get it to work right. (sorry nothing scientific here) After I installed the PCV kit this morning I'll have to make adjustments to the choke cable since it's slightly off due to the 1/4" spacer adapter lowering the carburetor.

[JOHN COOKSON]

I presume the choke butterfly moves freely. There may be a slight bend in the inner wire that is binding on the outer cover that is hidden inside the cover where you can't see it. Also is the outer cover secured at the knob end? The next step may be to let the entire cable loose and pull the inner wire out and inspect it.

TRUE GRIT

[joehinvt]

look closely and see if the bracket the cable clamp is on is bent outta angle some. look at the previous picture and then look at yours. its what i found on ours. not bknowing what a straight one looked like made it harder to diagnose.

[sastanley]

Ed..I'll chime that I had the same problem..no scientific method...In my case the cable (and armature) was bottoming out at the sheath...moving the sheath helped..but it was really trial and error..I agree with Neil that the return spring is secondary...since it is a solid cable, when you 'un-choke', the cable does 98% of the work.

Trail & error sir. The error needs to be on the fully closed side...adjust tha cable so the choke is fully closed, and then see if you have enough travel to open it after that. Good luck.

[sailhog]

I had a similar problem. I finally got it to work by removing about a half-inch of the plastic casing with an excto-blade. Then I cut a similar section of bicycle inner-tube (.5 inch x .5 inch) and wrapped this around the stripped section of casing. The rubber inner-tube section was a bit thicker and gripped the coil housing better. It also adhered better to the clamp. Once everything was tightened down, the housing stayed in place.

[tenders]

Definitely get rid of that spring. Worse than useless.

[Mo]

Hi Edward.

I put a new choke cable on the boat in 2007. Worked very slick and well for first year and I didn't lubricate it. Then it started to be hard to pull and push etc and eventually it was bent just as you say...at the carb end.

I picked up another choke cable for about $20 and it is going on it's 3rd season now. This one I spray with silicone grease when I find it's not moving slick...and in the fall prior lay-up.

Picked up the choke cables at a place called "drive-line products". These guys make up pull cables for heavy trucks, tractors ...the old way of shutting down diesels and the like. The casing is always long and I trim off what I don't want.

Since I've kept the cable well lubricated I haven't had that bending issue at the carb end. I know it shouldn't matter but in my case an easy sliding cable was the answer.

[edwardc]

Well for the time being, this has become a non-issue. I finally got everything plumbed and wired up and hit the starter. Even with the choke only 2/3 closed, it turned over twice and fired right up! Within 30 seconds, I was able to open the choke all the way without stalling. A few minor tweaks on the idle jet (from 1 1/2 turns down to 3/4 ) and on the timing, and I had a smooth idle at 750 RPM, and an even acceleration to higher RPMs both in-gear and out.

I even tweaked the new adjustable main jet from 1 1/2 turns down to 1 1/4 turns with no noticable effect at 2000 RPM.

After looking at the comments here, I suspect that there's a minor kink in the cable that doesn't bind when it's not clamped, but hangs up when its clamped. I don't know if this is the original cable or not, but it is NOT the unit that Don sells, as the knob is devoid of markings. It looks like it's plenty long enough for me to trim back a few inches of the core and case to try to get to a clean section, but its become a lower priority since the successful start.

[sastanley]

ed, good news...you just need to fiddle with it until it is right!

[edwardc]

Update

Well, I couldn't leave well enough alone, and had to go back and tinker with the choke cable. Can't seem to leave a problem unsolved. An engineer's occupational hazard!

Anyway, after first making it worse, I finally came up with a scheme that works. Studying the choke cable and carb carefully, especially the non-rotating barrel clamp and the return spring, led me to conclude that the carb was originally designed for either a braided, or very thin solid, flexible choke cable. Mine is somewhat thick and VERY stiff. The effort required to flex this solid cable as the choke arm went through its rotation is what was causing the cable to stop partway.

My (kludge) solution was to remove the wire from the rigid barrel clamp on the choke arm and bend a "U" shaped hook in it. The hook was placed so that it would just slip over the shank of the screw in the barrel clamp. This way, when it was pulled, there was no twisting force on the wire end, and it easily went all the way to full choke. The return spring insured that the screw always remained retained in the hook as the choke cable was released.

And it works great! With a stone cold engine, it now starts instantly as soon as I press the starter.