I'm trying to pass the new california smog.

My 79 F350 460 is running to high on the HC's.

Does turning the screws out richin or lean out the carb?

The screws are turned out about 4 turns right now,but the smog guy said to go up on the main jet about 3 sizes?

Now if the HC's are to high and I richin the carb wouldn't the HC's go even higher?

I'm totally confussed on what to do,anybody have a suggestion?

 

The general rule of thumb is high HC means it is running lean and high CO is rich. Before spending a lot of time on the carb I would make sure you do not have any vacuum leaks as that will significantly lean of the mixture.

To check for vacuum leaks first check that anything using vacuum is not leaking. Normal vacuum without leaks should be around 20”. Devices using vacuum would include the auto trans, brake booster, EGR, HVAC, and much of the emissions equipment. The best way is to see if you have any device leaking is to read the vacuum using a vacuum gauge. Read the gauge with the device connected and then disconnected, making sure the port it came from is properly capped off. Do only do one device at a time and if there is a higher vacuum with it disconnected then that device is leaking. Many devices have diaphragms that dry rot and then leak.

Then, after you know that all devices are not leaking, spray carb cleaner all around the union of the intake to the cylinder heads, around the carb, carb base, EGR plate, vacuum trees and along all the many vacuum hoses. Look for a brief increase in vacuum and idle speed. If you get it you have found a leak. Often the manifold will need to be retorqued to stop leaking and all those vacuum hoses are also subject to dry rot.

My motor had many vacuum leaks through lots of dry rot, but I have been able to get it up to about 21 by tracking down all leaks, setting the timing correctly, and then dialing in the carb.

Good luck,

Mark

 

Thanks Mark

I guess the timing should be set at what the sticker under the hood says, 8 degrees?

So high HC's is a lean condition?How many jet sizes should I jump up to?

Vacuum leaks, the only thing that I've found so far is on the back of the V V A the rubber block that the vacuum lines go into is missing and someone just plugged the vacuum lines straight into the V V A.

Two problems

1,three ports on the back of the V V A and only two hoses hooked up,what do I do with the open port?

2,which hose goes where?

Thanks, Vince