Truck is not running

[Kip7143]

Looks like it’s a Rochester varajet II

[jayoldschool]

All the info, and scroll down for the important idle speed info:

http://www.mbs.id.au/tuning/Carburet...er/Varajet.htm



The idle by-pass screw is the correct idle speed adjustment method used to adjust idle speed, not the low speed screw that contacts the primary throttle shaft. This screw controls the amount of air bypassing the throttle disc and therefore controls the idle speed. The idle mixture screw is usually sealed at factory but it can be adjusted to give a better idle quality. However be careful because it may cost you a little economy. These engines are specifically tuned lean, not for best vacuum or idle quality.

Base bench adjustment - Mixture screw out 3 turns. Idle by-pass screw out 2 turns

And, I'd agree with others, you need to find TDC and make a timing tab (and check/set the timing).

[Kip7143]

Hi all!

Sorry for the delay in work on the truck. It’s been a busy spring and working shift work doesn’t help. I’ve also been working on a 71 Pontiac (see picture) so it’s delaying the truck work a bit. But today I made some progress.

I removed the carb from the truck and found two things.

First is a screw at the bottom of the carb with a spring on it. The bottom end of that screw connects to an arm which is connected to the throttle. This tells me this is the idle speed screw. The stripped screw in the earlier pictures would be the fast idle screw. So question 1) when the carb is warm, should the fast idle screw still be on the cam, touching L, or does the cam disengage completely and the idle screw takes over?

Secondly is I think the mixture screw. Looks like a valve stem. I’ll add pictures so you can see and let me know!! Thanks for everyone’s help!!

[Kip7143]

And here is the Pontiac !!

[Kip7143]

Hello again,

Another update. I re-installed the carb and played with the idle adjustment. It’s running but still pretty weak. When I’m drive I have to hold the throttle or it’ll die. I was able to get it running soon after I installed the carb and set the idle speed while in drive… it seemed so promising! Let it sit and cool off for a while and then tried again and yielded the same results, sputtering and stalling.


Up to date: rebuild ignition, checked all plugs and wires.
Changed all vacuum lines
Checked timing (without a tab but it’s running its smoothest where it’s at)
Took the carb off and adjusted the idle speed and high idle.

Where do I go from here?