My carb is running very rick right now so i bought a vacuum gauge but im not sure how to use this correctly, but i do have an idea. Is there someone that can tell me how to set the carb or walk me threw the vacuum process step by step any thing will help. I am looking on line for some videos now but there is not much.
Thanks i looked at that one should i have the hose from the gauge connected to the manifold or one of the carb ports, if one of the carb ports then does it matter witch one?
Gary, A manifold port should be fine. If you are going to use a port on the carb for vacumm, it needs to be a manifold vacuum port. This means that the port needs to be on the carb base plate, not on the carb body.
Manifold vacuum. Doesn't matter if it is on the carburetor or intake, but it must be manifold vacuum. When you unhook it with the engine at idle, a manifold vacuum source will hiss and have strong suction. If you unhook a line and it doesn't hiss, that is a ported connection, and that is no good for a gauge connection.
Ok from what you guys are saying that seams like the passenger side top of the carb it hisses an has a strong vacuum. So to set the 2 mixture screws whats my next step ?
Start with both screws about 1 1/2 turns out. Adjust for highest vacuum. If your carburetor is running rich at idle, it is more likely that you have some other problem like throttle position and timing issues. Or the carburetor is flooding.
This is a new carb and my timing is at 0 tdc. should i turn down the throttle screw before doing this or leave it where it is
What happens a lot with Q-jet carburetors is the throttle is too far open, and the engine starts to run on the main circuit instead of the idle system. Fuel drips from the main nozzles and the engine runs very rich. The 1969 engines were meant to be run with the vacuum advance hooked up to manifold vacuum. That would give you vacuum advance at idle, and the timing would be more like 16* BTDC. That enables you to back off on the idle speed screw and close the throttles. Then you can adjust the idle screws and hear the engine respond.
now its starting to make sence so 0 tdc is where the distributor is set an i advanced it just past the 4 on my scale is this about right? An one other thing you said is that the advance should be ran off manifold right? So should i back off the idle to drop the speed an let the mixture screws do the idling
The distributor timing on a 69 engine is at 0, TDC. Plugging the vacuum hose from the distributor vacuum advance to a manifold vacuum source should advance the timing beyond 0, and speed up the engine. Then back off the idle speed screw to get the RPM around 8-900 RPM. Then play with the idle mixture needles for best vacuum.
so the 69 should run at about 800 to 900 on the idle?? Cause if so im to low she is almost at 800 an i have ac thats to low correct?
I just finish setting the mixtures an they sit right about 18 19 on the gauge 2 1/2 turns out. I drove up the block an got on her shes moving good, no gassy smell well just a tad, not like before.
