Throttle Travel and Drive Belt Questions

[76C10Stepside]

Just took my 1976 C10 stepside out of the garage for the first time in awhile. There are two issues that I'd like to resolve so I can start driving it again. Could use some help resolving these.

1. The throttle responds WAY too fast. Just a light tap on the gas pedal revs it right up. This problem started AFTER I rebuilt the carb, replaced the throttle plunger (which collapsed after rebuilding the carb), and finally anchoring the accelerator cable on the engine side. Before all this, it had very little throttle response. I didn't drive the truck much and just lived with it. I BELIEVE the reason the throttle is way too sensitive now is because the cable no longer slides when I press on the gas, but I'm not absolutely sure. A previous owner swapped in a V-8 from a Caprice, and it did not have the mounting bracket for the throttle cable on the intake manifold (was probably on the firewall in the Caprice). INFO:

• Carb is a Rochester 2GC "2 Jet" 2-bbl.
• The carb's throttle cam/lever has 1-3/4" of travel.
• The gas pedal has 2" of travel.
• Don't know how much gas pedal travel it takes to achieve wide open throttle.

Please see attached photo. Is the throttle lever/cam on this carb the same as it is on the trucks, or is it shorter?
The only ideas I've had to fix this are a) extend the length of the throttle cam/lever to get a longer ratio of travel, OR b) buy a new carburetor.
Anybody know what's going on here and how to fix it?

2. The drive belt for the power steering pump squeals like a stuck pig. I bought a new cut belt that was supposed to be the correct size (IIRC, it was the cheaper Gates), and it has squealed like this ever since. Have tried spraying Belt Ease and adjusting the tension. It's pretty tight now. Nothing I've tried helps. It's really bad when I first start the engine after it has been sitting. The belt LOOKS like it fits correctly.
Short of buying a high quality WRAPPED belt, any suggestions on how to fix this?

Thanks!

[geezer#99]

Put your throttle return spring in the front. Hook it up high as possible. You might need to make an 'L' type bracket for the end by the thermo housing. That'll stiffen it up.
What do you have for a throttle and tranny kick down bracket?
To check full throttle just unhook the throttle cable and stroke the carb wide open. Put the pedal on the floor and see if the cable moves far enough back to work.
Your squeeling belt could be from the wrong 'V' shape of the belt. Belt riding too high in the groove.

[cadillac_al]

The throttle spring looks weak to me. If it's as weak as it looks that will make it rev up quick.

[76C10Stepside]

I'd like to rule out the possibility that the throttle cam/lever on this carburetor is shorter than the ones used on the trucks or some such goofy thing. Does anyone have a picture of the 2GC/2 Jet on their Chevy truck that I can look at to see if they look the same?

Originally Posted by geezer#99

Put your throttle return spring in the front. Hook it up high as possible. You might need to make an 'L' type bracket for the end by the thermo housing. That'll stiffen it up.
What do you have for a throttle and tranny kick down bracket?
To check full throttle just unhook the throttle cable and stroke the carb wide open. Put the pedal on the floor and see if the cable moves far enough back to work.
Your squeeling belt could be from the wrong 'V' shape of the belt. Belt riding too high in the groove.

The throttle return spring has plenty of resistance and returns just fine (it's not jumping open). The problem is that the throttle opens up at too far too fast for the amount of pedal depressed. If I don't just tap it, it opens too far and leans out because it's getting too much air too fastl, then it catches back up and revs like hell. If I'm real careful on the throttle (and engine is warm), it runs great. This engine has a surprising amount of power now that the throttle is able to open up fully (since anchoring the end of the throttle cable)!

I'm not sure what you mean about making an 'L' type bracket for the end of the thermo housing to stiffen something up.

geezer, I don't know what I have for a throttle and trans kickdown bracket. Will have to take a look. Here's the back story...

I bought this truck from a used car lot. The engine had paint marks that said "'78 Caprice 305 ... OK ... hands off no parts" on it. About 6 months after I bought it a cam lobe went flat. I drove it like that for a year (not a daily driver), then rebuilt the top end (new cam, timing set and lifters). I looked for an id stamp on the block, but never was able to find one. Since all the parts I replaced are the same for both 305 and 350 blocks, I never did find out for sure which block it is, but it sure makes a lot of power now! After I rebuilt the carburetor, the throttle plunger collapsed, and a good samaritan on this forum sent me a good one, absolutely free! The new plunger is not exactly the same (looks way better quality, probably from an older carb), so I guess it's possible that it has something to do with the throttle being too sensitive.

The v belt looks like the right profile and height for these pulleys, but I'll take a picture tomorrow and post it just in case I'm wrong. I'm thinking I should just pay the extra money and get a quality wrapped belt. The cheap cut belts never seem to work very well.

I'll report back if/when I get these issues resolved.

[donut]

geezer hit on my thoughts for the v-belt and checking the stroke on the carb. IIRC, your throttle return should be a double spring. A weak spring can make your throttle erratic.

[geezer#99]

If you put the spring on the front you'll need somewhere to hook the spring up near the thermo housing. An 'L' bracket is but one way. You can buy them already made or make your own. Here's one. Looks just like an "L".
http://www.summitracing.com/int/part...4708/overview/

Take a pic of your throttle bracket at the same time. Sounds like your throttle cable isn't locked down right.

[76C10Stepside]

Ah, now I get what you mean. I really don't think my problem has anything to do with the return spring, but I will try it anyway if extending the throttle cam/lever does not solve the problem.

Autozone only had their cheapo brand cut belts for this truck. Will check the other stores. I've had the best results with Gates brand wrapped belts.

I'm looking forward to getting this truck spruced up! It will get black bedliner, new bed "wood" (charcoal Trex) with stainless steel bed strips and hardware, a new chrome back bumper and when I can get to it, new paint and interior. Any suggestions on a good paint color? It has a blue interior. Was originally a medium blue metallic.

[76C10Stepside]

You guys were right! I made a temporary 1-inch extension for the throttle lever and tested it. No improvement. Then I located a good return spring and hooked it up to pull the lever from the front (left the other spring in place). That did the trick. I removed the temporary extension and it still works pretty good. I will probably make a permanent extension though, as it was smoother with it.

Next thing is to fix the automatic choke, which always does the OPPOSITE of what it should do (yes, I tried flipping it around). The cheap manual choke I put on it does not work that great.

Thanks for your help!

[geezer#99]

Divorced choke?
Got pics??

[76C10Stepside]

Originally Posted by geezer#99

Divorced choke?
Got pics??

Next time I work on this truck I will take pictures of the choke and its guts. Maybe you can tell why it doesn't work right. For now, the manual choke is good enough in this warm weather.

I have other questions about little things on this truck. Guess I should create a build thread for it...