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Choke retrofit

For about a year the electric choke on my 1987 Mazda pickup has been burning out and it has finally given up altogether. I know this because I took it to a mechanic after I drove 10 miles on the highway with the engine revving at what sounded like near full capacity. To make matters worse, the car is old enough that finding a new electric choke switch is impossible for either me or my mechanic. Realistically, I can only expect the car to be reliable for two to three years more at the most so replacing the entire carburetor for $300 dollars is tough to justify. One Idea I have is to disconnect the electric element on the choke and retrofit it with a manual choke cable and lever which I would route into the cab. Is this a realistic option to get the truck to run smoothly for another couple of years? If so, does anyone have any tips on how or where to run the cable?

Manual choke retrofits are available for some trucks. I have an early 70’s Ford truck, and there is a manual kit available for it. I forget who the vendor is though, I found it using Google. Have you tried Google to see if one is available for your particular make/model?

No, I haven’t looked beyond just the cable at an O’Reily auto parts. I will look for that. I have also worked with a manual choke before on my dad’s '52 GMC pickup.

Sounds like a good idea.

I like to drill a hole or look for the biggest rubber grommet and shove the cable through, right beside whatever else is there. Remember not to drive for long with the choke partially closed because the fuel metering device in the carb will adjust for choke position and could cost you some fuel economy and could foul the plugs.

Sure! You can install a manual choke on the dash. You just have to rig it up.

But then you must become accostumed on much choke to apply to the given cold start condition, and for how long.

Tester

What you need is a cable which you have to modify to attach to the point where your electric choke now fits. The attachment will take some basic rigging, and as Tester suggests you will have to play with it to see what is open vs closed. I rigged a throttle cable from an old lawn mower as a choke on an old pickup . . . worked fine and the cable came through the firewall easy enough, I didn’t even put it in the dash I simply let it lay on the floor and covered it with floormat when I wasn’t fiddling with it. The cable I used had two click positions, a rabbit and a turtle, and clicked into position making adjustment a little funky. Next time I’d look for something which is more adjustable, no clicked positions. know what I mean? Anyway, strip off the old electric and go for it. Cheap and easy. Rocketman

How cold will your winter be, choke? If your climate is somewhat mild the choke can be opened fully and the engine started by pumping the gas repeatedly before cranking and continuing to pump a few seconds after starting. Then holding the rpms up for a minute or so until the engine is able to idle and it is driveable.

I had an 83 Toyota Tercel where the automatic choke died. I bought a manual choke cable from the local auto parts store for $12. I unscrewed the cover of the automatic choke, removed the mechanism to expose the end of the choke that stuck out of the carb. I connected the cable to it after running it through the firewall and screwed the choke control into the dash below the steering wheel. I quickly learned how much choke to give the car to get it started and how quickly I could open it. It worked that way for 5 years and almost 100,000 miles before the car finally died at 260,000 miles.

Yes, you can do this and it should work fine. Using a manual choke will take a bit of trial and error but you’ll learn what works best quickly. Biggest issue with manual chokes is some people forgot to push the knob in, which opens the choke fully, and drove around with a warm engine and the choke on. Lots of black smoke and pollution of the motor oil.

Where the choke connects to the cable, you’ll need to plan for some “swivel” action at the connection. You also need to find a place to mount a sturdy bracket about 6" away from the choke somewhere on the motor (block, or intake manifold). Inside the cab locate a spot for the cable to pass through the firewall, I’d look for the place where the accelerator cable passes through and use a hole (or drill a new one) nearby.

Buy the hardware and buy the cable about 2’ longer than you think you’ll need. You can trim it as needed later. The extra length will come in handy when installing it and will give you room for “gentle” curves in the cable once installed. I’d spray some cable lube in the cable before installing it to make sure it is well lubed and this will help it all work smoothly.

Just curious, but has your mechanic verified that the choke heater is really burnt out or is it due to a lack of battery voltage being provided?
Many Japanese vehicles have the choke wiring fused so one would hate to overlook that.

Personally, I would try to fix the electric choke. If a Mazda choke can’t be found then what about adapting an electric choke from something else? I’ve done this in the past with very little effort.
The last car I had that had a Quadrajet on it also had a Nissan choke heater and a Ford carburetor had one from an old Subaru.

I shoulda done that on my 59 Pontiac years ago and it would have saved some starting headaches. One thing I don’t understand though is how the choke is causing high reving? You sure its the choke and not the high idle for warm up?

I kinda like the direction that Bing is going in. Isn’t the electric part just for setting the choke? It sounds like setting the choke isn’t the problem, the problem is in the vacuum choke pull off. Those diaphragms eventually rot away and have to be replaced or they cause the conditions you describe.

Some of these Japanese carburetors had a two stage choke pull off system, two diaphragms, two separate vacuum hoses. Often mechanics overlook one of them.

Thanks for all the advice everyone. I’m finding conversion kits for about $20 but there are also cables by themselves that I think I could rig with some cold weld and basic hardware. Any advice on which of these would work best? The kits usually look like they have some plastic pieces which I’m a little suspicious of in terms of longevity.

I think you should spring for the $20 kit. The plastic pieces should hold up just fine. I bought a choke conversion kit for my 1955 Pontiac. It installed in less than 10 minutes and never gave a problem. As I remember, some of the parts were plastic.

I’d go with the kit too. You can spend a lot of time and effort trying to make and fit your own parts. I wouldn’t be using any plastic weld.

Most manual choke kits contain enough parts so you can get it rigged up. They usually work better than the original choke EVER did…1987 could be tough, those last carbureted vehicles used some pretty strange carburetors…Find a choke kit that says it will fit your vehicle…The Mazda and Ford Ranger are the same truck, making finding parts easier…