72 C10 WOT Throttle Adjustment?

[Rich72C10]

For WOT I really have to push on my gas pedal, heck I more or less need to stand on it firmly. When I push my pedal to the floor and peak at the throttle position through the windshield, it isn't going as far as when I do WOT by hand on the Carburetor's throttle bracket. It almost does but not quite.

So that got me thinking, how do you adjust the cable to bite more into the throttle? I thought behind the metal mounting bracket it looked like an plastic turn adjuster but it barely moves in either direction. From the C10 Chevy Service Manual, when I disconnect the cable, move the cable back and then by hand put the carb in WOT, the nubby mount on the throttle bracket and nearly cable line up.

In my photo the shield/sleeve is a bit distorted, which it has always looked like this. I assume this is because this sleeve (protector?) is smashing up on the mounting bracket.

I even thought perhaps I should get a new cable, so the sleeve isn't messed up and perhaps it would adjust better. I only found one place, Classic Parts but I don't think I have bought from them before. So I am cautious.

[BigBird05]

The trans dentent cable isn't keeping you from getting WOT is it?

[Rich72C10]

I don't think so, I did that little adjustment when you are WOT and let the TV Cable cable pop and put its catch back into place.

Just a bit ago, I loosened up the carb bolt for the throttle bracket and push it towards the firewall (there is a bit of play for the bracket when the carb bolt is loose). Now I don't have to stomp hard on the gas pedal to the floor, so that definitely helped in my test drive. I need a helper to push on the pedal while I can be under the hood. Kind of hard to see things from inside the cab on this.

[pjmoreland]

I don't know how it is supposed to be, but I'm wondering if it would improve things for you if you moved the attachment point of the cable to the empty hole that is what looks like about 1/2" lower down on the carb. It would pull your cable out a little farther at idle, and it would make your carb open at a faster rate compared to pedal displacement.

Oh, and I've ordered many things from classicparts.com without issue. I've generally been happy with the quality of the stuff they sell.

[Rich72C10]

I also wondered about that other hole.... I suppose I could give that a test drive in that position.

[LockDoc]

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If moving the pivot point doesn't cure it I don't know why you couldn't trim the cover/sleeve a little bit. That would get rid of the distorted area and give you more clearance on the bracket/rubber isolator.

I would highly recommend Classic Parts. I have been to their showroom a few times and purchased many parts from them. They carry the best replacement vent window gaskets I have found. They are also a sponsor of the All Truck National Show in Riverside, Missouri.

LockDoc

[HO455]

This is a pretty common issue. Slop in the mounting holes for the bracket, mismatched cable and bracket, thick carpeting, pad and sound deadening material preventing full designed pedal movement, bent throttle pedal or bent bracket on the carb. Any or all of these together could cause your issue.

[Rich72C10]

Thanks guys, I suppose at least you haven't pointed out something I am doing crazy wrong or missing.

My truck does have sound deadening material, then the black cardboard stuff on the firewall that has insulation backing, nice carpet, and then my floor mats.

Seeing there doesn't seem to be a lot of options to buy the 72 Throttle cable I am getting it and I'll put mine up for a spare. I'll also try trimming the cover/sleeve a little bit, as Leon suggests, I didn't even think of that (along with the pivot hole change).

Thanks guys!

[Rich72C10]

Okay then, changing to the other pivot hole, as pjmoreland first suggested worked. Now when I go to the floor the secondaries kick in, just like when I would move the throttle by hand to WOT. On my test drive not only can I feed it kick in and I hear a sh*t ton more coming from the Qjet secondaries kicking in. Best of all, all I have to do is go to the floor and not stomp it hard (most times before I'd have to stomp twice).

The pedal movement is a lot firmer too, not sure if this is bad or good. But I am not finding/feeling any odd effects when not going WOT. I even loosened that back carburetor bolt and put the bracket back, so it wasn't forced back to the firewall. Which I didn't like doing as it looked a bit janky looking being off center.

Edit:
jerry-rigged my iPhone to take a video, then took a still frame of WOT from me pushing the pedal to the floor. Now without hard stomping the secondary mech thingys engage fully (in yellow circle). The Red Arrow is where I moved my throttle cable pivot from/to.

Edit 2:
On my second test drive (after readjusting the bracket off the back carburetor bolt) I had my iPhone App running for my Progression Ignition. From full stop to punching it to the floor my vacuum now drops to zero, where as before my throttle cable change it would drop to 2~3. I assume that is all good (though bad for MPG LOL).

[Rich72C10]

Getting a video was challenging, used my iPad Pro. Which I almost dropped when I took off. Looking at my video editor, 0-60 took 10.17 seconds. Not going to win any drag races that's for sure LOL


Video may not be embedded if you are using https for the Truck Forums (which you should be using https) - so just click the banner to get to YouTube.

72 Chevy C10 LWB SBC 350 - Nailing Pedal to Floor