i have an 84 f150 with a 351w
The guy i bought it from put a brand new holley 4 bbl carb
i cant get it too pass emissions.
they say it is running to rich.
how do i adjust the fuel mixture?
thanks

 

Been over a decade since I messed with a holley, there should be 2 screws/bolts at teh base in the front. One for each primary. Turning them to the right leans it out, left richens it up. Depending on how rich you are, ussually an 1/8 turn or less each is all the adjustment you want to do at a time. Always turn both the same amount.

 

That only adjusts the idle mixture. If it's too rich off idle, you need to rejet the carb.

 

Could be many things. If its a new carb they come jetted for sea level so it may need adjustment there. Most likely its something else. Tuning issue maybe or a vacuum leak. My mach I wouldn't pass for the longest time I had to find a shop that would let it slide. Finally figured it out it had a bad brake booster causing a vacuum leak. Probably your problem is something like that. In my car I treid everything I could think of including replacing the carb and Jetting it down. Until I found the leak it would not pass.

 

well ill try adjusting the carb tomorow.
then ill start tracking down vacuum lines and make sure everything is right.
thanks for your help!

 

inspect vacuum lines the most common problem

 

i'm curious
here emmision requirements are very lax

but i didn't realize a carb could even pass modern emmisions standards

 

Emissions tests started here in the late 70's. Most cars had carbs then. Here in Utah everything new then 68 has to pass..

 

Also, when was the last it got a full tune up?
If it's been a while try that.

Might try slightly warmer plugs atleast for the test, retarding the timming, just a little bit.. just for the test. If your running to high of fuel rating then that would cause it too because it's burning to slow so not burning it all before compression is released. Don't know what your running, but might try the next step, numerically down, if applicable.

A couple of years ago the original guys on Horsepower TV, took a 1969 camaro straight out of a scrap yard. Did nothing other than give the engine a through tune up including rebuilding the carb but that was as indepth as they got in it. Then put it on the sniffer. It was beating every brand new vehicle right off the new car lots, that they could find to put against it.

Just an engine running properly, tuned and dialed in.
I hope we never start the sniffer, but I fear it's coming someday in the next decade.

 

I think they have to meet the standards of when they were built, they probably couldn't meet the new ones.

 

Absolutely correct. I also believe anything with OBD2 does not have to sniff, it's simple code check.

 

That's how Missery works... which would explain why my 1999 F-150 with no cats could pass the emissions test.

 

I pay $7 and they give me a sticker. Sometimes, if I'm really lazy, then I even take the vehicle with me and then they'll put it on for me.

Z I htink thats just St Louis county, I dont think anywhere else in the state currently has any type of emiisions. Move your residence outside St louis county and your golden for a few more years. All you have to do is set up a PO box in Rolla and presto thats your new residence! No emisions testing there.

 

They tried telling me I needed to emissions test my trailer first, then my diesel. I laughed at em. And I'm pretty sure its STL and KC that need to be emissioned.

 

I remember that.

Yea Kansas Town and maybe even Jeff Town too.