GCV160 Auto Choke Issue

[SpoolinV70]

I've been trying to sort out the choke on a GCV160 powered Craftsman lawn mower, and I'm getting a bit frustrated. I initially ordered a replacement carburetor with a manual choke lever, which I soon realized was incorrect, as this mower has an auto choke lever. Got the correct carb, installed it, and the auto choke isn't working properly. It doesn't ever adjust, it just keeps the choke flap closed.
Now the problem is that this engine seems to have the only Honda auto choke design that I can't find any information on. The later thermo-wax style choke is well documents, as well as the semi-auto choke design. This one is a little different though, as it seems to be a thermo-wax setup, but it's integrated into the whole choke lever assembly.

I did find it on parts diagrams, however the part isn't listed. I'm assuming the only problem is the wax element, as the springs and lever are all working smoothly. Does anyone know what I could do here? Would I be able to just swap to the other thermo-wax auto choke lever? I already have the wax element for the other style, but I'd have to double check the engine casting to ensure it as the opening in the right spot for the thermowax element.

Part 21 in this diagram https://www.jackssmallengines.com/j...n-gjaea-1000001-to-gjaea-5386302/carburetor-2

Pics:

New item by Alex P

photos.app.goo.gl

https://photos.app.goo.gl/U5HUPVLeeHd7wwiF7 (the element itself that I removed from the housing)
https://photos.app.goo.gl/sLrupe8X95xArP9Z6 (the back is loose since I had removed the screw, taking it apart to inspect)

 

[StarTech]

Make sure you have looked up the correct GCV160 series and type number IE the type number must be the correct one along with the serial range.

 

[SpoolinV70]

I'll double check the casting on the block, but this should be correct.

 

[Sandman73]

I've been trying to sort out the choke on a GCV160 powered Craftsman lawn mower, and I'm getting a bit frustrated. I initially ordered a replacement carburetor with a manual choke lever, which I soon realized was incorrect, as this mower has an auto choke lever. Got the correct carb, installed it, and the auto choke isn't working properly. It doesn't ever adjust, it just keeps the choke flap closed.
Now the problem is that this engine seems to have the only Honda auto choke design that I can't find any information on. The later thermo-wax style choke is well documents, as well as the semi-auto choke design. This one is a little different though, as it seems to be a thermo-wax setup, but it's integrated into the whole choke lever assembly.

I did find it on parts diagrams, however the part isn't listed. I'm assuming the only problem is the wax element, as the springs and lever are all working smoothly. Does anyone know what I could do here? Would I be able to just swap to the other thermo-wax auto choke lever? I already have the wax element for the other style, but I'd have to double check the engine casting to ensure it as the opening in the right spot for the thermowax element.

Part 21 in this diagram https://www.jackssmallengines.com/j...n-gjaea-1000001-to-gjaea-5386302/carburetor-2

Pics:

New item by Alex P

photos.app.goo.gl

https://photos.app.goo.gl/U5HUPVLeeHd7wwiF7 (the element itself that I removed from the housing)
https://photos.app.goo.gl/sLrupe8X95xArP9Z6 (the back is loose since I had removed the screw, taking it apart to inspect)

I feel for you, these auto choke systems are riddled with design flaws.

Check out these documents, it may help clarify replacement parts. The thermo-wax, control arm and governor spring were all replaced (redesigned) on my version of the GCV160.

The Section 6 of the troubleshooting manual looks like your control arm? It won't let me upload the manual so here is the link:
http://www.ipspower.com/images/docu...buretor-Troubleshooting-Manual-Compressed.pdf

 

[SpoolinV70]

I feel for you, these auto choke systems are riddled with design flaws.

Check out these documents, it may help clarify replacement parts. The thermo-wax, control arm and governor spring were all replaced (redesigned) on my version of the GCV160.

The Section 6 of the troubleshooting manual looks like your control arm? It won't let me upload the manual so here is the link:
http://www.ipspower.com/images/docu...buretor-Troubleshooting-Manual-Compressed.pdf

Thank you so much for posting these! I actually ordered the element shown as part #3 (16620-Z1L-841) in the first PDF attachment. That seems to be the correct thermowax assembly for this style auto choke. Weird, I guess Honda didn't use these for long, since I can find very little info on them. Everything you see online for the thermowax-controlled ACS is the later style.

Fingers crossed that this finally gets my auto choke working.

 

[sgkent]

kind of off the subject but we run into these same issues on some old collector cars. Sometimes the devices are common enough and they can be found in the shower industry where there are lots of designs for temperature regulating units. One fellow in a forum I belong to found a way to repair the brass ones. One can crimp them a little with a flat punch in a vise, and they will work many more years until more wax leaks out or whatever it does when they fail. It may be that over time the housing simply balloons a little from the pressure so hitting them with a flat punch removes the additional volume. Heat the new one slowly in water measuring with a fine thermometer to see what temperature it begins to open. Then use that to calibrate the old one with a flat punch - as a spare. Or order a couple more because you will be replacing it again.

 

[SpoolinV70]

I installed the wax element, and it seemed to work yesterday, and now today it seems to be either heating really slowly, or not at all. I don't know if it's because the linkage on the choke assembly is bent or what. Really annoying at this point... I should just swap it for a manual choke lol.

 

[Sandman73]

I installed the wax element, and it seemed to work yesterday, and now today it seems to be either heating really slowly, or not at all. I don't know if it's because the linkage on the choke assembly is bent or what. Really annoying at this point... I should just swap it for a manual choke lol.

Yep, I almost burnt my lawn mower on the driveway.. for the $2 I would replace the spring, assuming you have the larger one. It came up to speed instantly (therefore hotter really fast) once I had the new (smaller) spring.

 

[Sandman73]

I installed the wax element, and it seemed to work yesterday, and now today it seems to be either heating really slowly, or not at all. I don't know if it's because the linkage on the choke assembly is bent or what. Really annoying at this point... I should just swap it for a manual choke lol.

After looking a little closer to your pic, I think that is the old control arm?

What wasn't obvious to me is that the wax piston will not retract just because it cools off. That control arm spring is what pushes it back in as it cools, the new arm has a different spring setup on my mower.

 

[SpoolinV70]

It doesn't seem to be working either way. After a while, I noticed that the linkage had extended, and I was able to tweak the arm to keep the choke open once it was hot. Ran fine.
Then today, it didn't seem to extend at all. The spring holds it closed pretty tightly.

Is there an updated part? I can't seem to find anything on that linkage or springs.