What could cause this?

What could cause this? - 06/20/11 03:52 PM

My 440 sixpack at start up is running great after 1/2 hr or so of street driving the car starts to run sloppy and stall at every stop sign and red light. The engine has a comp cam# 21 227-4.timing at 10 btdc engine compr 9.7/1. Also when I am trying to start it at this point fuel shoots out of center carb like a fountain....fooled with mixture screws still cant get it to run right. I let the car cool...drive it again starts all over. Also checked timing does not jump. Thanks Rob

Posted By: Andrewh

Re: What could cause this? - 06/20/11 05:00 PM

if fuel is shooting out of it, you either have too much pressure(electric fuel pump) or floats are not set right. or some combination of the two.
mixture will not help.

Posted By: yellow sixpack

Re: What could cause this? - 06/20/11 05:27 PM

No electric fuel pump here.

Posted By: Andrewh

Re: What could cause this? - 06/20/11 05:31 PM

could also be heat build up in the carb presurizing it. but I would say that should not last long.

either way, recheck your float levels first.

Posted By: bboogieart

Re: What could cause this? - 06/20/11 05:34 PM

I would have to agree with the float adjutment. When the engine is cold it needs more fuel as air is more drnse. When it warms up it starts flooding. Hope this makes ence to you. Also how is you choke set?

Posted By: Viol8r

Re: What could cause this? - 06/20/11 05:34 PM

Pull the needle and seats......clean them. Stuck float.

Posted By: CUDA8U

Re: What could cause this? - 06/20/11 07:02 PM

I WOULD SAY ITS A OVER FUEL PROBLEM OR BAD COIL......COULD BE A CHOKE STICKING OR THE FLOAT IN THE CARB AND IF YOUR RUNNING A COIL THEY CAN GO BAD WITH TOO MUCH HEAT.SOMETIMES IT COULD BE A BAD PLUG.

Posted By: terzmo

Re: What could cause this? - 06/20/11 07:04 PM

choke may not be coming off

Posted By: RapidRobert

Re: What could cause this? - 06/20/11 08:04 PM

Minute debris in the gas letting the float leak/bad needle & seat assy/needle & seat or float mechanically hanging up in its range of travel/idle psi on the edge of too high. I'd replace the filter if any doubts about it's veracity and sub in a new needle seat assy & reset the level & go from there. EDIT meant to say minute debris letting the needle/seat leak

Posted By: yellow sixpack

Re: What could cause this? - 06/20/11 10:14 PM

Thanks...all good stuff for me to ponder anything else would be apprecited...nobody think electrical?

Posted By: bboogieart

Re: What could cause this? - 06/21/11 12:08 AM

CUDA8U seggested the coil might be getting heat soaked. (?)

Posted By: CUDA8U

Re: What could cause this? - 06/21/11 12:23 AM

READ CAREFULLY.......FUEL OR COIL PROBLEM!!!!

Posted By: bboogieart

Re: What could cause this? - 06/21/11 12:27 AM

Yep but the O.P. asked about an electrical source for his problem and I just mentioned what you said. READ CAREFULLY AND TURN OFF THE CAP LOCK PLEASE.

Posted By: maximum entropy

Re: What could cause this? - 06/21/11 12:48 AM

is your heat riser blocked? fuel is most likely boiling in the center carb. try putting race gas in it (much less volatile) and see if it's ok.

Posted By: pishta

Re: What could cause this? - 06/21/11 01:02 AM

Friends Nova did this after 5 minutes, bog and die and flame out when starting. it was fuel pressure related off a blue pump. contaminated seat would do the same.

Posted By: Pacnorthcuda

Re: What could cause this? - 06/21/11 01:06 AM

Quote:

Pull the needle and seats......clean them. Stuck float.

I would suspect a needle & seat issue.

Posted By: yellow sixpack

Re: What could cause this? - 06/21/11 01:13 AM

I did read about the bad coil just wondering about the orange box heating up and shutting down should have been more specific I guess.

Posted By: Pacnorthcuda

Re: What could cause this? - 06/21/11 01:35 AM

Quote:

Thanks...all good stuff for me to ponder anything else would be apprecited...nobody think electrical?

You say this: "Also when I am trying to start it at this point fuel shoots out of center carb like a fountain."
And you are asking if it could be electrical? I suppose if you were also having backfire issues (as in a distributor installed 180 degrees off, or mixed up plug wires) but absent that condition your problem most definately is fuel related.

Posted By: yellow sixpack

Re: What could cause this? - 06/21/11 12:58 PM

It did backfire once.

Posted By: DAYCLONA

Re: What could cause this? - 06/21/11 03:24 PM

Quote:

It did backfire once.

Backfire on the trio of Holley 2300's isn't a good thing, you may have ruptured the power valve in the center carb,....I would start with establishing that all 3 carbs have a properly set fuel level, just ebbing out the brass sight hole plug is your minimum setting on the end carbs, I like to use clear Holley sight plugs to set all 3, center carb I usually set at halfway in the "window".......to check to see if your Power Valve is toast without pulling it and performing a vac check, you can turn the air/fuel idle screws located on each side of the metering block of the center carb all the way in, if it stalls your power valve is good, it it's still idleing, it's junk....

Posted By: MoparforLife

Re: What could cause this? - 06/21/11 04:15 PM

Also make sure that the needle and seat is shutting off properly. If it has been doing this for very long I would highly recommend : First get to the root of the problem then change the oil and filter. Flooding like this gets gas into the oil and gas diluted oil is a very poor lubricant. Get it out of the there, the sooner the better.

Posted By: RodStRace

Re: What could cause this? - 06/21/11 04:20 PM

Yep, change the oil and filter, then go through the carbs. Fuel shooting out the vents is NOT electrical!

Posted By: crlush

Re: What could cause this? - 06/21/11 06:03 PM

Quote:

Quote:

Pull the needle and seats......clean them. Stuck float.

I would suspect a needle & seat issue.

needle and seat, garbage in fuel bowl, or no gas tank vent, which is pressurizing tank and overcoming needle and seat, when it does it unscrew your gas cap and see if you get a rush of air.

Posted By: 70Cuda383

Re: What could cause this? - 06/21/11 06:29 PM

Quote:

READ CAREFULLY.......FUEL OR COIL PROBLEM!!!!

hey, cuda8u, read carefully...turn off your caps lock!!!!

I' say again... TURN OFF YOUR CAPS LOCK!!!!

SEVERAL MEMBERS HAVE ALREADY POSTED REPLY'S TO YOU, ASKING YOU TO TURN OFF THE CAPS LOCK, IT MAKES IT LOOK LIKE YOU'RE YELLING!!!! EVEN IF YOU'RE NOT, THAT'S HOW THE MIND SUBCONSCIOUSLY SEES FULL CAPS LOCK!!!

Thanks. It also makes it easier to read when it's not full caps.

Posted By: RobX4406

Re: What could cause this? - 06/21/11 07:56 PM

IMO, you don't have enough initial timing at 10BTDC with that cam. Try 16* or more. If you give the engine more initial and it picks up RPM, it wants that additional timing. I generally put as much initial on it as it will take, still start when hot, no starter kick back or straining starter.

You'll have to limit the distributor mechanical advance to hit your desired total timing.

Fuel shooting out the carb is a bad thing and needs to be addressed as mentioned. Most likely dirt in needle/seat or it's just bad, stuck/sunk float. Get that fixed up. Make sure your fuel filter is good and you don't have rust in fuel line/tank.

Here's a really solid write up on 6 pack tuning from the tech section.

http://www.moparts.org/Tech/Archive/fuel/7.html

Get the initial figured out and reset your idle adjustments.

Posted By: 62maxwgn

Re: What could cause this? - 06/21/11 08:33 PM

Quote:

Thanks. It also makes it easier to read when it's not full caps.

Not if you have bad eyes !!

Posted By: 73rrak

Re: What could cause this? - 06/21/11 10:30 PM

The next time it does it stop and take the fuel cap off and see if it stops doing it. The vent in the gas/fuel cap might be plugged.

Posted By: yellow sixpack

Re: What could cause this? - 06/22/11 04:29 PM

Thanks guys all great stuff going through it all.
Rob

Posted By: bboogieart

Re: What could cause this? - 06/22/11 05:13 PM

Quote "or no gas tank vent, which is pressurizing tank and overcoming needle and seat, when it does it unscrew your gas cap and see if you get a rush of air"

Two posts to this affect.
I believe this is backwards, the tank would not be pressurized but would become a vacuum tank and not allow gas out. The woosh you hear is air getting sucked back in. Think about it. Suck gas out of a none vented tank. How would that creat positive pressure. An electric pump could over pressurise the needle seat though. Needs a return line.
I agree on changing you oil pronto. Always remember oil is cheaper than iron.

Posted By: 451Mopar

Re: What could cause this? - 06/22/11 05:34 PM

Quote:

My 440 sixpack at start up is running great after 1/2 hr or so of street driving the car starts to run sloppy and stall at every stop sign and red light. The engine has a comp cam# 21 227-4.timing at 10 btdc engine compr 9.7/1. Also when I am trying to start it at this point fuel shoots out of center carb like a fountain....fooled with mixture screws still cant get it to run right. I let the car cool...drive it again starts all over. Also checked timing does not jump. Thanks Rob

If fuel is coming out of the carb you need to fix that first. Check fuel pressure should be 3-5 psi, Check needle and seat assembly, and that the "O" rings are in good shape. If the "O" rings are bad fuel will go around the needle and seat and flood the carb. Also remove the float and shake it to make sure fuel is not getting inside the float. I had a float with a pinhole in it and it would run fine for a time, but then fuel would get into the float and sink it, then the carb would flood.