Heavy, over-rich upon starting. Why?

elgecko · #1 (**permalink**) 12-10-2010, 04:13 PM

Trying to get this thing tuned. My Cobra has 390 Fe, C4 automatic, Holley 750 vac. sec., auto choke. Cam is comp cam, solid lifter Magnum 282S, 282 duration. 571 lift.
Upon starting, I have a rough time keeping it going. Black, rich smoke from pipes, both sides. Won't idle. Have to keep giving it gas.....more smoke. If it then sits for a few minutes, it fires and runs a little better.
Checked the float bowls.....fuel is below sight holes.
Fuel pressure is 6 lbs.
Choke is set at index mark from factory.
Could it be a vacuum leak problem?
What should the vacuum read with this setup?
It's always something

Thanks
dave

madmaxx · #2 (**permalink**) 12-10-2010, 04:19 PM

Dont pump gas before you start it, lean choke a little more. Either you are giving it to much gasoline or not enough air.

DanEC · #3 (**permalink**) 12-10-2010, 05:04 PM

Sounds like the choke is closing down to much causing it to run rich. Try moving the choke adjustment to the lean side.

Dwight · #4 (**permalink**) 12-10-2010, 05:56 PM

remove the choke and use the gas pedal.

If your going to sit in the car till it warms up, then use the gas pedal. Forget the choke.

Dwight

elgecko · #5 (**permalink**) 12-10-2010, 06:37 PM

Going to check that choke, probably go with a manual setup choke.
Got to get this on the road soon.

JBCOBRA · #6 (**permalink**) 12-10-2010, 06:41 PM

Got to get out and beat it hard to blow it out. It will run much better after that.

patrickt · #7 (**permalink**) 12-10-2010, 08:12 PM

Quote:

Originally Posted by elgecko

Going to check that choke, probably go with a manual setup choke.
Got to get this on the road soon.

I would bet your air bleeds are clogged. Take five minutes and clean them out as per this thread. Then take it for a ride and report back. Holley Carb Woes - DCDoug Pay Attention (Long Post)

elgecko · #8 (**permalink**) 12-10-2010, 08:51 PM

Good piece of advise. I'll try it this weekend. Sure wouldn't hurt.
Thanks

madmaxx · #9 (**permalink**) 12-10-2010, 09:02 PM

Wow, excellent tip. Mine does run rough when started and will blow a little black smoke, I will definelty give this a try!!!! Thanks!

Quote:

Originally Posted by patrickt

I would bet your air bleeds are clogged. Take five minutes and clean them out as per this thread. Then take it for a ride and report back. Holley Carb Woes - DCDoug Pay Attention (Long Post)

patrickt · #10 (**permalink**) 12-11-2010, 11:52 AM

Here's a nice little thread on this subject, with lots of pics, one of which I'll copy below: http://www.pro-touring.com/showthrea...nger-Corrosion!!

madmaxx · #11 (**permalink**) 12-11-2010, 12:46 PM

I tried Patrickt suggestion and I cannot remember the last time it ever idled as good as it did this morning when cold. No smoke, no rocking of the engine like an ignition miss, just idled higher (choke on) as compared to normal. I used to sit in the driveway and let it idle when cold until it did not pop and miss thinking it was normal. Always idled good when warm or so I thought, it appears to even idle better warm, I dropped the rpm's down to 800 from 850.

I will try again tomorrow moring to confirm cold idle improvements.

My concern is how have I been on this forum for 5 years and now only find out about this incredible tip. Should this not be a sticky or something, I would bet more than half of us have holley carbs. I will say this you get a nice back spray of gumout when you do the inner holes, LOL. Luckly I had covered the fenders and associated componets with towles before I started.

Thanks again Patrickt!!!!!!!!!!

patrickt · #12 (**permalink**) 12-11-2010, 12:56 PM

Quote:

Originally Posted by madmaxx

I tried Patrickt suggestion and I cannot remember the last time it ever idled as good ...

Thanks again Patrickt!!!!!!!!!!

Yes, I know, I'm great.

But you watch, ERAChas is still going to be mean to me, even on a thread singing my praises.

Dwight · #13 (**permalink**) 12-11-2010, 04:03 PM

praise to patrickt

Bobcat · #14 (**permalink**) 12-11-2010, 04:26 PM

As Patrick pointed out ... ethanol is BAD . It also eats rubber fuel lines and that can also clog the carb . Look at Peterson Fluid Systems Series 700 inline filters that screw directly into the carb inlets as they have a stainless steel mesh filter ... I believe it`s about 60 microns . Stay away from the sintered bronze filters in the inlet as I have had the ethanol attack those also . This is the same unit the NASCAR boys run on their carbs ... and what I now use as a final filter to the carb . Price was around $37/unit and I got mine from CV Products in NC .

madmaxx · #15 (**permalink**) 12-12-2010, 03:52 PM

It worked, it was COLD this morning. Car fired up, no sputtering, black smoke etc. Solved a problem I did not even know I had.

THANKS

patrickt · #16 (**permalink**) 12-12-2010, 04:06 PM

Quote:

Originally Posted by madmaxx

It worked, it was COLD this morning. Car fired up, no sputtering, black smoke etc. Solved a problem I did not even know I had.

THANKS

You're welcome. Many, many years ago, I used to do "no parts tune-ups" for my fraternity brothers in college for, like, $25 (or something of that relative worth

). That included cleaning and gapping the plugs, setting the timing and dwell, inspecting the distributor cap and sandpapering the electrodes clean, cleaning the air filter with gasoline, and cleaning and adjusting the carb. Cleaning out the carb with spray cleaner, including the air bleeds, made a huge difference, even in the non-ethanol 70's.

I'm glad I was able to help you -- you might want to add a "quick squirt" to your bi-monthly maintenance schedule.

Buzz · #17 (**permalink**) 12-15-2010, 05:59 AM

Quote:

Originally Posted by patrickt

I would bet your air bleeds are clogged. Take five minutes and clean them out as per this thread. Then take it for a ride and report back. Holley Carb Woes - DCDoug Pay Attention (Long Post)

Tuning tip of the month award!! Some of my bleeds were obviously clogged when I squirted the fluid. After clearing them out - what a difference in startup and driveability below full operating temperature. Damn Cobra almost feels too civilized now!

patrickt · #18 (**permalink**) 12-15-2010, 06:41 AM

Quote:

Originally Posted by Buzz

Tuning tip of the month award!!

Yep, frankly, I continue to amaze even myself.

elmariachi · #19 (**permalink**) 12-15-2010, 06:54 AM

This is good stuff. Its always the little things that bite you.

Pat, an entire DC driving season has come and gone and I don't recall you having posted any new pictures of you driving your car. Have you put it back in the plastic bag yet?

patrickt · #20 (**permalink**) 12-15-2010, 06:57 AM

Quote:

Originally Posted by elmariachi

Pat, an entire DC driving season has come and gone and I don't recall you having posted any new pictures of you driving your car. Have you put it back in the plastic bag yet?

Yes I have. Read this ongoing thread: http://clubcobra.com/forums/showthre...hreadid=108084
This year I basically spent more time under my car than driving it. But she's fit as fiddle now and waiting for spring.



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