Accelerator Linkage Adjustments

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gregg hake
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Accelerator Linkage Adjustments

#1 Post by gregg hake » Tue Jul 09, 2019 1:39 pm

Hi all,

So I started my rebuilt engine (1962B S ) after 20 some odd years of life getting in the way (engine sounds great so far), and the idle is screaming high because the linkage from pedal to carbs was installed by a rank amateur (me).
1st of all, I have the Service Manual (appears to be a photocopy of) that I bought from one of the Registry vendors a decade ago, and I find out it is missing the pages that explain the whole linkage adjustment thing. I also have a digital version that someone sent me a few years ago unsolicited, and it too is missing those same pages.

In reading all the posts on adjusting the linkage, the starting point is measuring the distance form the center of the ball (behind the shroud) to the shroud and verifying it is 50 mm. Mine is 40mm.
1. Are we measuring this distance with everything at rest or with the linkage at "full throttle" position?

2. After adjusting the vertical push rod to its maximum length (as suggested by several members), where do I make adjustments to change the 40mm distance to the desired 50mm? On the carb linkages or on the Bell Housing end?

Thanks Much, Gentlemen.

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David Jones
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Re: Accelerator Linkage Adjustments

#2 Post by David Jones » Tue Jul 09, 2019 1:55 pm

Greg, just disconnect it and set the length to 50mm then adjust the carb down linkage to get a tiny amount of slack with the carbs adjusted to idle with the linkage off. Now go back and adjust the pedal to bell crank linkage.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

gregg hake
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Re: Accelerator Linkage Adjustments

#3 Post by gregg hake » Tue Jul 09, 2019 3:06 pm

David...well, that just makes too much sense !

Thank you !

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PaulLima
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Re: Accelerator Linkage Adjustments

#4 Post by PaulLima » Tue Jul 09, 2019 4:48 pm

I've attached the appropriate pages. I'd start with step one on pg SF26 (fig. 8) with the carb linkages disconnected and, probably, the pull rod down to the bell crank on the trans. You can see the 50 mm measurement, but also note that the down pull rod is parallel to the bell crank arm. If you get this one right, the others become pretty obvious. For me, the next step would be to get the two down links to the carbs right. As a starting point (assuming the idle screws are set for equal idle flow) adjust the down links to get a tiny bit of wiggle in them (i.e. no tension). Check by moving the vertical link on the front of the fan shroud slightly and watching the two carb arms. You want them to move off the stops at the same time. Then set the pull rod for "no preload or tension" when you hook it on the tranny bell crank and snap to the bell crank on the front of the shroud. This should get you pretty close.
Carb linkage.pdf
(164.51 KiB) Downloaded 69 times

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Herlin E. Woolery
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Re: Accelerator Linkage Adjustments

#5 Post by Herlin E. Woolery » Tue Jul 09, 2019 9:36 pm

Hey Paul,
Would the PDF Carb linkage work for the A cars?, I added insulators to my Zenith carbs and did throw off my linkage somewhat and the hand throttle needing more adjustment also so just got to keep at it.
Herlin Woolery
58' A coupe 104120

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PaulLima
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Re: Accelerator Linkage Adjustments

#6 Post by PaulLima » Wed Jul 10, 2019 9:31 am

I plead ignorance. The info came from the B-C shop manual and I'm don't know if it is accurate for an "A".

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David Jones
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Re: Accelerator Linkage Adjustments

#7 Post by David Jones » Wed Jul 10, 2019 10:36 am

There are differences between the "A" and B/C but that is mainly the updated link between the throttle rod from pedal to bell crank and the bell crank itself. The "A" bell crank does not leave any room for error but the later bell crank has a better "throw" giving more movement at the shroud bell crank otherwise the system is the same.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

gregg hake
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Re: Accelerator Linkage Adjustments

#8 Post by gregg hake » Wed Jul 10, 2019 3:20 pm

PaulLima wrote:
Tue Jul 09, 2019 4:48 pm
I've attached the appropriate pages. I'd start with step one on pg SF26 (fig. 8) with the carb linkages disconnected and, probably, the pull rod down to the bell crank on the trans. You can see the 50 mm measurement, but also note that the down pull rod is parallel to the bell crank arm. If you get this one right, the others become pretty obvious. For me, the next step would be to get the two down links to the carbs right. As a starting point (assuming the idle screws are set for equal idle flow) adjust the down links to get a tiny bit of wiggle in them (i.e. no tension). Check by moving the vertical link on the front of the fan shroud slightly and watching the two carb arms. You want them to move off the stops at the same time. Then set the pull rod for "no preload or tension" when you hook it on the tranny bell crank and snap to the bell crank on the front of the shroud. This should get you pretty close.Carb linkage.pdf
Thanks Much, Paul.

Ill be busy this weekend !

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PaulLima
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Re: Accelerator Linkage Adjustments

#9 Post by PaulLima » Wed Jul 10, 2019 5:45 pm

You are very welcome.

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Herlin E. Woolery
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Re: Accelerator Linkage Adjustments

#10 Post by Herlin E. Woolery » Wed Jul 10, 2019 9:51 pm

Thank You all and will be doing more adjusting for my A coupe
Herlin

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Jim Clement
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Re: Accelerator Linkage Adjustments

#11 Post by Jim Clement » Wed Jul 10, 2019 10:06 pm

is it pages 149 and 150 you are looking for ?
 

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Jim Clement
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Re: Accelerator Linkage Adjustments

#12 Post by Jim Clement » Wed Jul 10, 2019 10:57 pm

are these the two you are looking for ?
my apologies for the poor attachment method.. I should be able top do better tomorrow with some better PDF software
Attachments
page 150.PNG
page 150.PNG (144.34 KiB) Viewed 129 times
page 149.PNG
page 149.PNG (180.24 KiB) Viewed 129 times
 

gregg hake
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Re: Accelerator Linkage Adjustments

#13 Post by gregg hake » Thu Jul 11, 2019 3:06 pm

Hi..I think my missing pages are SF25 and 26, which Mr. Lima sent me. It looks like yours are related to linkage also, so please forward those to me if you can.

Thanks Much
Jim Clement wrote:
Wed Jul 10, 2019 10:57 pm
are these the two you are looking for ?
my apologies for the poor attachment method.. I should be able top do better tomorrow with some better PDF software

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Jim Clement
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Re: Accelerator Linkage Adjustments

#14 Post by Jim Clement » Thu Jul 11, 2019 5:45 pm

this should be a bit better.
I see that I have attached it.. ..not sure it is there..
Attachments
356A carb linkage.pdf
(960.38 KiB) Downloaded 27 times
 

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Alan Winer
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Re: Accelerator Linkage Adjustments

#15 Post by Alan Winer » Thu Jul 11, 2019 9:47 pm

This might help
Throttle Linkage.png
Throttle Linkage.png (238.96 KiB) Viewed 67 times

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