Throttle cable not always returning to idle

[skydiveD30571]

VP 5.0 GL-H with 2 barrel Holley.

I notice that sometimes when returning to neutral detent on the control, the idle speed sometimes rests about 100-150rpm higher. This seems to happen more often during cooler days, but still happens randomly on any day. I can manually push the throttle bracket on the carb and it drops down to normal. I removed the cable from the bracket and saw no change, meaning the carb doesn't close that last little bit on its own. When closed correctly, idle speed is 700rpm and 650 in gear. Obviously this little extra rpm make shifting a burdon and I know its hard on the drive.

I also noticed the cable has a bit of free play. As a test with the cable disconnected from the throttle bracket, I pushed the control to the WOT position, then returned to neutral. The throttle cable connector was about a 1/4" off of the bracket, but by slightly pulling the cable the free play was taken out and they aligned correctly.

Earlier this year I adjusted the cable to provide a little force to close the carb when at idle. It seems like since then, the cable may have developed some more play?

Without the free play, the cable pushes the carb closed and all is good. With this play, there is no pushing force and the carb doesn't close all the way on its own.

My question is, how much play is normal on a throttle cable? Is it normal for a carb not to close that last little bit without a small amount of push? I'm sure I could adjust the cable again to force it closed, but since it sometimes does and sometimes doesn't return to the normal position, I'm afraid of adjusting that and causing other problems. As always, thanks.

[Don S]

Adjust the throttle cable end so there is slight preload pressure on the carb linkage toward the idle position.

[skydiveD30571]

I did that in April. Basically, sometimes it provides pressure, sometimes not. The difference is the cable freeplay. I'm wondering how much free play is normal. Right now I'd say 1/4" - 1/2" is what I see. Is it worth replacing the cable, or just adjust it again and call it good?

[Don S]

Push the free play out of the cable then adjust the cable end.

[skydiveD30571]

Will do Don thanks. Just making sure it won't cause any other problems. I'll wait to replace the cable.

[skydiveD30571]

Push the free play out of the cable then adjust the cable end.

I assume you mean push the cable into the outer sheath, then adjust the throttle connector? The service manuals talk about "pulling" the cable end to remove the free play, but that seems like it won't help my situation. Currently mine is adjusted so that pulling out the free play in the cable lines up the connector with the carb linkage. Push the control lever to wot and return to neutral, and now the connector is not lined up.

Sounds like pushing the cable in to remove the play is the only chance, except the service manuals disagree.

[Don S]

You are doing it by the service manual and it doesn't work. Push it in and try it.

[skydiveD30571]

Was replacing my shift cable and decided to just throw in a new tfxtreme cable for the throttle too. Before switching out cables, I tried pushing the play into the cable and adjusting the throttle cable connector. That method seemed to do the trick.

Absolutely no play in the new one. I was surprised how much shorter the throttle stroke is now...there was quite a bit of slack in the original cable.