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Fluid Drive manual downshift issue solved


harmony

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Over the years I've read that many owners of the Fluid Drive have to push the gas pedal right through the floor in order to get the car to downshift when it's needed. Sometimes with success and sometimes without success. The later being my issue since I purchased the car. Finally I decided to investigate . I did the trouble light test and the bulb lit up just fine once that plunger was depressed about 8/10th of the way in. Which told me the issue had to be something mechanical. I propped a stick between the seat and gas pedal after adequately protecting the front of the seat with a piece of plywood. Once I was confident that the pedal couldn't go any further down, by even removing any carpeting that might get in the way, I check the location of the lever bracket that would engage the plunger on my Carter B&B carb, that would in turn set off the process of downshifting. The arm on that bracket was still about 3/16 in. away from making contact with the brass plunger arm. For some of you that might not be familiar with the set up, the round shaft that the throttle plate is fastened to is round as it comes out of the back of the carb and then the last portion has a flat section on it. Which marries up the the "D" shaped hole in the bracket. Meaning it can't be adjusted in a clockwise/counter clockwise rotation. Since the idle needs to be at 450 rpm and not 3000 or so rpm, there's no way that plunger in the carb will ever get depresses, by adjusting the gas pedal linkage arm, at least on my car.

So I got a piece of UHMW plastic and made up a spacer attachment on my bandsaw to slip over the activating arm section of that bracket. It now works like a dream every time. I just happened to have white UHMW about the right size, but now that I have the shape I need and I know it works, I'll probably make it out of black UHMW so it doesn't visually stick out like a sore thumb.

What still baffles me is why there was so much of a gap between the plunger and the bracket when the gas pedal was depressed as far as it would go. My other 3 Carter B&B EV1 carbs and carb throttle brackets are the same.

carb linkage modification2 (2).jpg

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3 hours ago, Doug&Deb said:

Someone cut that part off of my linkage. I welded on a piece of carb linkage that has an adjustment screw. Doesn’t look pretty but it works like a charm.

Interesting that you went that route.  I gave that some thought but since my bracket was original I didn't want to bastardize it.  But I thought about drilling and taping a hole in that arm and them putting a machine screw so the action was similar to the idle screw, like what you did.

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The linkage rod lengths have been changed.....making the throttle lever tab not able to push the kd sw. plunger.

The throttle  linkage can be adjusted to fix this issue.

But you did fine.

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