So a problem I'm having is that the throttle return spring on the weber carb on my truck isn't strong enough to pull the throttle all the way closed. It'll get it close, and the. Eventually get it there but an example, I set the idle to 800, snap the throttle a few times, and then it will be idling at 900. There will be a bit of wiggle room in the throttle and if I manually give it some assistance it'll go back down to 800, or if it just idles for 5 minutes or so it will also eventually work it's way back down. Either way, not as quick as I'd like.
So my initial thought was to try to find a stronger spring. I did sort of that, at the suggestion of a chap over in mightyram50.net I simply added a second spring.
There isn't enough room to just double that spring right there so I needed to find another spot to mount it. I noticed this post coming off of the intake that had a threaded hole at the end. I figured that would be perfect as it is also located almost directly below the throttle cable connection as well. Since the throttle return is in a downward rotation that meant I can just hook a spring right there pulling down and it should work.
So what I needed to do first was to drill a hole in the cable hookup for the spring to connect to.
Then it was just a matter of getting a bolt to go in that hole, which was an M8 x 1.25. I got one that was 30mm long. I decided to do the hook up a little different, and we will see if it works out in the long run. Instead of just looping it around the bolt I drilled another small hole in the head of the bolt. The problem I was running in to, and this could probably be sorted with a 35 or 40mm bolt, but the 30mm was just short enough that when fully tightened down it would start crushing the side of the spring. So hooking it on the end prevented that. It also gives me a little bit of fine tuning with the spring tension.
And that really is all there was to it. You can definitely feel the difference in the pedal, it's heavier but the action on it seems more direct. There isn't the initial slop in it that there was before. My only concern is that full throttle might stretch the spring enough so it slips back out of the hole, but we will see. Fortunately the worst case situation here is that it slips and then the throttle is back to how it was before. Nothing that would kill the truck though.
It does get it right back down to the idle I set too. Which is nice.