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The choke o matic doesn't work. I have to manually push the choke up to start the engine. What is required to correct the operation of the choke o matic?

Usually it is because the throttle cable has slipped under the clamp just far enough so the tab on the throttle linkage no longer pushes the choke all the way on.
Set the lever in the dash to choke position, loosen the clamp bolt slide the cable till the choke fully engages then tighten the bolt
Do not over do it as there is only about 2 turns of thread to holt the bolt in place.
I regularly end up gluing a nut behind the plate because KING KONG has over tightened the screw .
One of the few places that red loktite is allowed to be used.

Thanks for the help. This is indeed the problem. However, the cable is "weak" and bends a little when in fully throttle position and the choke lever is not pushed up. I'll see if I can adjust it to engage the choke. If not, I'll need a new cable -- but, they're not cheap!

Take the old one to any mower repair shop .
Most will have bulk cable and Z benders.
I charge $ 10 (AUS ) to make a cable.
If your inner is bending and not moving the controls then the coltrols need a touch of lubricant or heaven forbid a clean .

Also can be the choke binding or simply not adjusted to push it close at max throttle. Not always a cable adjustment problem.

Thanks again. I've attached a couple of photos so you can see what I mean by a bend. The cable moves easily to the point where the mechanism, which engages the choke, needs to turn and then it won't go any farther unless I push with my finger on the place where the red arrow is. It takes quite a bit of force with my finger to get the choke to move -- more than what the cable mechanism can provide without bending. Is the cable the wrong one here? The motor definitely won't start unless I push with my finger. Also, looks like this part isn't designed correctly as I don't see how the cable is supposed to make it turn as there is a lot of force required. I tried spraying everything with WD40 and nothing changed. Any help I can get would be greatly appreciated

The choke isn't binding as I can easily push that up with my finger. What is hard to move is where the red arrow is in the photo. Where I push to move the choke isn't shown in these photos. I was told that the engine was brand new when I bought the tractor which is 10 years old. It shows no dirt or anything representing a lot of use

Most Intek 20 hp that i work on is the single cylinder . This is a v-twin so please post the model number and type numbers. Also most these the cable pull to go to full throttle, yours seems operating right the opposite so it needs to mount on the left side and not the right side.

Somewhere there will be an adjuster for the choke lever that has backed off or totally fallen out
Once you get the throttle control to the the position in photo2 it can not go any further which is why the cable bows out.

The engine is a 20hp Intek twin. 40N877-0004. The tractor is an L120 about 10-12 years old. As far as the direction of the cable, I would expect the cable to "Pull" the lever and not "push" it as it currently does. I don't see any way of reversing this.

As far as something falling out, etc. The throttle lever pushes the bracket so far and then the cable begins to bow. I can push the lever further with my finger which then activates the choke and the engine starts fine. However, it takes quite a bit of pressure to push the lever further so I'm wondering what could be wrong as I'm positive that the current cable setup would not activate it correclty

Tomorrow or the next day I'm going to Home Depot which has a whole bunch of John Deee tractors on display and see if they have something similar in terms of the choke mechanism and see if I can determine how those are supposed to work.

Thanks everybody for your help. I hope everybody is staying safe.

OK now we get the entire story
That mower originally came out with a 407777 engine and was fitted with a separate throttle & choke cables with a 2 barrel carb
The 40n877 comes with only 2 variations & a single barrel nikki carburettor
Some on has fitted the 40N877 that has come from a mower with a auto choke without swapping all of the controls from the 407777 to the 40n877
The throttle levers on choke 0 matic controls have more movement than those with a dedicated choke so you are going to need to fit a complete choke cable including the bracket on the manifold .
There is also 6 different throttle controls and 4 of them are different choke O matic ones that were fitted to the original 407777 .
I have a feeling that you will need a longer control linkage that goes from the throttle control to the choke.
I always suggest that JD owners get a JD technical manual even when you pay for them they will repay themselves 10 times over in a very short space of time
In the cable section attached you will see where I got this copy from.
Their engine section is actually better than the offical Briggs & Kohler engine manuals.

From what I see the throttle is a pusher. The reason it bending it you have reach you have reach the outside edge of the rotation plane. An example is to take the round ring start with you hand next now start rotating the ring with you keeping your hand in position on the ring once you get your hand furthermost away it can't rotate any more no matter how pressure you put on it.

On the following image I think you are pushing at the area that the orange arrow indicates to close up gap bewteen it and the tab to the left. Is this correct? If so change cable to routed as indicated by the red line; of course, you need to move the cable clip. The yellow arrow indicated hole for the cable z bend end to go into.

Yes, the JD mower has slots for a choke and throttle but only a throttle lever as the engine was replaced with the one with the choke o matic. The page you attached looks like what the original engine would have looked like. I would love to get a service manual for my current engine. I couldn't tell where to find it from your attachment. Thanks for your help

For the second reply yes, the orange arrow is where I am moving that bracket to engage the choke except I am pushing from the front and not the back where the arrow is. It then rotates further and there is a "clicking" sound as if there is a tab or something that is offering resistance to the rotation. I can try moving the attachment point to where you recommend

My tractor forum , search for manuals .
This site does not have a facility to store documents
My tractor does

or you can buy it from JD as a download , disc or paper ( cheaper left to right )

If it were me I would buy a choke cable and the choke bracket.
The lever in the dash will not have the "full throttle - no choke" detent that choke O matic ones have so you will always be guessing if you have fully opened the choke .

Problem solved -- thanks everybody for your help. Indeed, the cable was attached at the wrong place. I went to home depot looked at a JD tractor there and the attached picture is how it is supposed to be hooked up. I easily moved the cable to this attachment point and everything works fine now. It is now a "Pull" action and not a "Push" action and the lever position now matches the speed diagrams on the dashboard

That was what I was wondering if you a pull or push throttle setup. What I was describing was the push setup.