Manual choke conversion for Federal CD-175's?

[JGeezer]

I was hoping to just can this awful automatic smog choke mess:

and I found a CD-175-2 really cheap on eBay, with a manual choke on it. I hoped it could be adapted, but now I see the CD-175-2 has this passage:

that goes all the way though to behind the throttle plate:

while the CD-175 has that blocked off completely:

so this approach is not going to work.

Anybody out there have a manual choke conversion for federal CD-175's?

[oldelanman]

Rather than starting with your existing carb and trying to fit the choke assembly from your "new" one could you perhaps do it the other way round - fit the air valve and cover assembly and any linkage bits necessary from your "old" to the "new" carb body ? You might need to change the jet as well, particularly if it is worn.

No idea if this approach is practical but might be worth a try having got this far.

[JGeezer]

Yeah, I've been thinking (you know, what one does at 3 AM) about doing exactly that.

First, it would serve me right for getting the old CD-175's almost rebuilt already!

I know nothing of the CD-175-2 provenance, but I guess if I swap in the needle & seat I shouldn't have to worry about imbalance too much. I see a number of other minor differences, such as the CD-175-2 not having the vent valve for the float chamber, also for emissions:

This is so when the throttle is closed vapors go to the line to the carbon canister. Grrr - It was absolutely frozen solid and it took me hours to get it cleaned up and freely working! I has started with these rough beasts:

There's also no linkage on the manual choke for the CD-175-2, as in this pic I found:

just this:

Choke8.JPG (20.43 KiB) Viewed 960 times

I'm getting that impending nightmare feeling again .

[JGeezer]

Everybody ready for something insane? I've converted the CD-175 emissions carb to a manual choke using the choke parts from the CD-175-2.

To do this, I had to drill out three passages that were left blocked in the emissions carb, including this long one

and add a fuel pickup extension using a bit of 3/16" brass tubing. Luckily, I'm far removed from the engine being able to run that I won't know what an idiot I am for awhile yet.