Runnig too rich

[clinck]

Okay Gearheads...hep me out.

I got Jeff's car yesterday and have logged a few miles. Initially the car would not idle so I advanced the idel screw and brought her up to 1000 rpm. Now she is running rich.You know, burn your eyes rich. I am not a mechanic but would like to learn how to solve this myself. Do I need to re-jet the carb. Arizona is dry with little humidity. The car came from Wisconsin. They have more moisture. Does that have anything to do with this running rich situation.
I know that carburators are sensitive to barometric pressure, humidity and elevation. I live in the desert with average 12% humidity and we are at 1100 feet sea level.
I guess I could take it to my speed shop and they will charge me who knows how much for a tune up and a possible re-jetting of the carb. I've never excaped without a $400.00 bill from them.
Is there a more reasonable answer?

Regards,



Sundown

[pgermond]

There are a number of things that can cause this.... jets, yes, but probably something a lot simpler. Is the choke sticking/working? Not knowing what you have for carburetion leaves a lot of unanaswered questions. Octane/timing................?

Phil

427 Roadster, #4279436
Southern Automotive FE
3:31 and Toploader

Roseville (N.Cal)

[clinck]

Good ole Phil...

There is no choke on this Biggs carb... I don't have a timing line and furthermore I don't know how to use one. I have seen the process over the shoulder of maechanics and I know that advancing or retarding the timing is done by rotating the distributor. Beyond that I am lost.
Sorry to be such a dummy. I got kicked out of shop at 14 years old and never learned the basics. I guess I'm doomed to the speed shops..

Regards



Sundown

[GeorgiaSnake]

Sundown I have zero knowledge on the Biggs, however my Holley was doing the same thing. I bought a few books and searched the web until I had the information I needed.

I could have bought a BG but I'm kind of stuborn when it comes to fixing things. To date I have put in a quick change secondary spring kit, removed the choke and set the idle mixture using a vacuum gauge. Next on the list is cut the choke horn off, change the power valve, try smaller jets and a few more tricks. The car runs much better now and seems to improve with every modification.

Randy

Unique 289 FIA
Southern Automotive 396
Team III 16's
Brilliant Silver

[clinck]

Hey, will I do any damage running the motor too rich beside fouling the plugs?
I know that this is not the best scenario but I will have to drive the car to the shop which is 30 miles away.
Thanks

Sundown

[clayfoushee]

Sundown,

I answered on your other thread, but I'd first turn that "idle screw" that you first adjusted, back in the original direction. Are you sure it was the idle adj. screw?

If the car is running well 2K RPMS and above (e.g. not missing, etc.) you're not hurting anything to drive it.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[nolastyankee]

Sundown,
My 289 FIA is still being built but in the mean time I am driving a '66 Mustang GT with a well worked over 289. Among other things, I have Edelbrock heads, intake, and a 0.500 lift cam. I moved from Utah to Wisconsin two years ago and went throught the reverse of what you are doing right now. Utah (Ogden) is at 4800 ft. with similar humidity and I live on the other side of the state from Jeff Karnitz. (Until I move tomorrow, but that's another story)

Having talked to many race shops on the subject, the conclusion that I came to was that carb jets should change by about 2 sizes (i.e. 72 to 70) to compensate for the reduction in elevation. This is what I ended up doing to my carb and it runs great. However, 2 jet sizes is very little and will not solve a 'burn your eyes' over rich problem.

I don't know about the Biggs carburetors, but I had a blown power valve on my Holley which caused a similar problem. Holley PV's are notorious for being damaged with a nice fat backfire, and when they are bad they dump fuel like crazy. I would think a competition unit like yours would have a circuit to protect from this type of damage.

Something to consider...These engines tend to run fat when they are cold. I have two nice exhaust stains in my drive from cold starting the Mustang. It stinks for the first couple minutes, but settles right in when the choke opens up. I'll attribute some of this to the aggressiveness of the cam, I also know that I have some adjusting left to do.

Like Clay says, don't worry about not being an expert. Every expert there is did something for the first time at some point in their life.

Unique 9122 - 289 FIA Cobra - The Legendary "Spence" Car

[clinck]

Hey nolastyankee,

I appreciate the words. I am very sensitive to every little thing she's doing right now. I'm trying to get a grip on what she is does and how she acts. Kinda like a first date I will check the plugs this afternoon to see what they look like. If their black then I gotta figure that she's runnin fat. With no lead fuel these plugs don't exactly look like they used to. I remember the good ole days when gas was gas and Hi Test meant more lead. Gone forever now.
I will take her to my mechanic and get her on a scope next week. We'll sort her out in no time. I am just afraid to run her anymore than neccessary to avoid any more fouling if that's the case.

See you later and thanks again for the advise.

Sundown

[clayfoushee]

Sundown,

As you said, you can't tell the condition of the plugs by looking at them anymore on unleaded fuel. They'll be black regardless of whether it's too lean, too rich, or just right. Remember.....a little fat (rich) is good, and they should always be rich when first starting up and often at idle.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[clinck]

Clay, Always appreciate your wisdom...er..what ever you call a friend's advice.

Keeping you posted brother,,



Sundown