-6 throttle cable(resurrection) Options

[914andy]

Things are progressing well...engine runs,carbs clean, fresh oil & filter, clutch is working and now adjusted.
It appears to me that the only thing closing the throttle is the return spring on each bank of carbs. When working the carbs from the engine bay everything is ok. Using the peddle ...not so good. Linkage pivot shaft on carb is cleaned and lubed...Pivot shaft on trans is cleaned and lubed.
Looking at the parts diagram...is the throttle cable 2 pieces? Do you have to remove the female end of the ball socket to get it out of the tube in the tunnel? I'm thinking there my be some crud in the tube/ tunnel. Any other springs that I might be missing?
Thanks for the positive comments and of course all the help
Andy

[brant]

could the throttle cable be wrapped around something in the tunnel? creating the extra drag?

try disconnecting the cable from one end and feeling the amount of drag as you pull from the other end... there should not be any.

[gereed75]

All one piece. When you remove the threaded socket fittings, cable will just pull through the tube. Cant recall if it is easier to work from engine side or pedal side, probably engine side.

Remove cable, inspect, replace if worn, lube and clean. Never tried to clean inside tube but a piece of cable frayed on the end chucked into a drill would probably serve nicely as a brush

Adjust so that all of the linkages have optimum angles - pulling tangential to the pivots. The whole assembly is a bit Rube Goldberg so optimal angles are important.

Final adjustment should be done so that there is a tiny bit of slack at idle and at full throttle the pedal should hit the stop just as the throttles touch their full throttle stops. I stand beside the open engine lid then use a broom handle snaked through the steering wheel to depress the pedal with my left hand and I can just reach in the engine bay to see if the throttles are full open with the pedal on the stop with my right hand.

I have installed a third spring between the linkage and a bolt on the blower shroud near the ignition coil, just to augment the two stock springs.



The whole thing is just rube enough that it has to be in pretty good shape and adjustment to work well.

[914andy]

Thanks... of to see what I can find.
I like the idea of an extra helper spring...will investigate that for sure

[gereed75]

Saw this arrangement once on a race car. Nice thing is it pulls both throttles cloesed.

[IronHillRestorations]

You've got to take the ball socket and jamb nut off the cable to pull it through the tube

[wndsrfr]

All one piece. When you remove the threaded socket fittings, cable will just pull through the tube. Cant recall if it is easier to work from engine side or pedal side, probably engine side.

Remove cable, inspect, replace if worn, lube and clean. Never tried to clean inside tube but a piece of cable frayed on the end chucked into a drill would probably serve nicely as a brush

Adjust so that all of the linkages have optimum angles - pulling tangential to the pivots. The whole assembly is a bit Rube Goldberg so optimal angles are important.

Final adjustment should be done so that there is a tiny bit of slack at idle and at full throttle the pedal should hit the stop just as the throttles touch their full throttle stops. I stand beside the open engine lid then use a broom handle snaked through the steering wheel to depress the pedal with my left hand and I can just reach in the engine bay to see if the throttles are full open with the pedal on the stop with my right hand.

I have installed a third spring between the linkage and a bolt on the blower shroud near the ignition coil, just to augment the two stock springs.



The whole thing is just rube enough that it has to be in pretty good shape and adjustment to work well.

Also check that your spiral springs on each throttle butterfly shaft are intact--one on front and back end of the shaft on my PMO's, assume it's same on Webers. It's hard to see those but have been known to fail. Do you also have the vertically mounted spring on the front bellcranks up to the tab under the air cleaner base? That's a total of 6 springs. The additional one he added is nice overkill but adds more tension on the cable & pivot points.
Pop off the cable at the rear of the trans & feel the cable movement by hand--should be super smooth. If it's not, it's possible it's dragging across the clutch cable right at the front end of the tunnel....

[ctc911ctc]

I would check this thread

http://www.914world.com/bbs2/index.php?sho...mp;hl=ctc911ctc

[914andy]

Once I had the front and back ends disconnected, cable feels good...as in no drag anywhere. So I think the cable is fine.
I'm coming to the conclusion that it is the bell crank? portion on the trans.
I have nylon bushes in there ...ordered some bronze....
The question now is are both attachment points supposed to be 90 degrees to the shaft?
Seems something to do with this and how the linkage up to the carbs goes. The linkage is not rubbing on the engine tin. Maybe this is part of the rube goldberg stuff.
Off to check out the latest theory
I took a look at the other thread...not the problem ...this time.
(IMG:style_emoticons/default/blink.gif)

[johnhora]

Is your trans bell crank a 914-6 one or 911....they are different....if 911 it will put a bind on the parts working...there are pictures around just can't find one at the moment.

[Mark Henry]

I only have the 2 Weber springs, it can be done.

I replaced the drop links with a pair I fabricated using 1/4" ball joints. You can see the straight one in the pic below, the 1/3 side is bent so the link is square to the throttle shaft, fine adjustment is done by bending the bent (1/3) drop link. The play in the old Weber drop links was outrageous. Also took a bit building/sorting the trans pivot point, cable routing, etc.
Nothing binds in my linkage, I have a nice light pedal.

(IMG:http://www.914world.com/bbs2/uploads/post-26-1497554034_thumb.jpg)

[porschetub]

I found bushes were worn out @ both bellcranks the engine side one was very worn.
Replaced the bushes in both and somewhat better then replaced most of the linkage ball cups and had to readjust everything ,no more "lost motion" and much smoother.
IMO its a fairly complex system and everything needs to be up to the mark,also makes tuning the carbs easier.
Good luck.

[wndsrfr]

I only have the 2 Weber springs, it can be done.

I replaced the drop links with a pair I fabricated using 1/4" ball joints. You can see the straight one in the pic below, the 1/3 side is bent so the link is square to the throttle shaft, fine adjustment is done by bending the bent (1/3) drop link. The play in the old Weber drop links was outrageous. Also took a bit building/sorting the trans pivot point, cable routing, etc.
Nothing binds in my linkage, I have a nice light pedal.

(IMG:http://www.914world.com/bbs2/uploads/post-26-1497554034_thumb.jpg)

The spiral springs are also there...around the shaft at front & rear of each carb....here's a link to a picture--no affiliation...
https://www.partsklassik.com/p-3034-throttl...g-ida-rflr.aspx

[Mark Henry]

The spiral springs are also there...around the shaft at front & rear of each carb....here's a link to a picture--no affiliation...
https://www.partsklassik.com/p-3034-throttl...g-ida-rflr.aspx

Yes, I forgot about those, so really the original Weber 2 springs per carb, no extra springs.

[Retroracer]

Is your trans bell crank a 914-6 one or 911....they are different....if 911 it will put a bind on the parts working...there are pictures around just can't find one at the moment.

(IMG:style_emoticons/default/agree.gif) This is a really good point; they look similar but are different. Also note the comments about the angles for each "translation of movement". This could explain it feeling correct from the carbs, but not from the cable. So you might have the correct bell crank but poor adjustment....

Photos of your set up would help!

- Tony

For reference:

[914andy]

It turns out that the trans bell crank was bent. Successful trips around the neighbor hood and no stuck throttle. I always thought that the half moon in the linkage was to be on top so as to allow more clearance for the CV joint travel. The last pic looks like the rod is upside down to me.
I will be adding an extra spring ...just seems like a good idea. The carbs only have the one spring located at the front of each.
I do appreciate all the help given. I think its been about six years since I have seen or been able to puts hands on the car. Its slowly coming back to me (IMG:style_emoticons/default/beerchug.gif)

[roblav1]

I'm about to do this in a different way today on my conversion. Run the stock /4 cable up in front of the engine and fabricate a horizontal bell crank attached to the top of the engine. Cable pulls going forward while the rod to the carbs pulls aft.

[914Toy]

I have an 8' long similar diameter generic cable (purchased at a marine supply parts shop) that is similarly located as the stock cable but is turned 180 degrees from below and after the passenger side axle up to and through the stock cable hole in the engine tin, and the cable sheath is anchored with a clamp on the original accelerator bracket on top of the engine, and another clamp near the heater lever in the tunnel. This is simple with few moving parts and has worked well for the past three years. I believe the cable is typically used in steering linkage on outboard powered boats!

[914Toy]

Correction, I bought a 10 ft cable which fits perfectly.

[fixer34]

Had mine out, took a picture. I added a large return spring on the bellcrank many years ago. Never had a problem since.