truck sputters

[kelz702]

Hey guy! I been having an issue with my truck(1972 c20 original 350) right now. When I floor it, the motor starts to sputter. This started about 3 days ago. Before that, it was running like a dream. Its bogged down a few time while driving it normal but for the most part, it runs good. Haven't had any problem starting up or while idling. Since I bought it, I've put on a new Edelbrock 600 carb(9 months ago) 2 new fuel pumps(4 months ago), fuel filter, and gas tank(2 months ago). I also did wires and plugs not to long ago. I would greatly appreciate any ideas or help anyone could give me.

[geezer#99]

You might have too much fuel pressure making it flood a bit. Eddy's like only 5.5 psi.
And your timing could be off.
What's your timing set at?
Does it sputter when fully warmed up?

[kelz702]

Originally Posted by geezer#99

You might have too much fuel pressure making it flood a bit. Eddy's like only 5.5 psi.
And your timing could be off.
What's your timing set at?
Does it sputter when fully warmed up?

Hey Geezer, Thanks for the reply. Yes, it sputters when its warmed up. It's mainly when I step on it. I haven't checked the timing yet. Im waiting for my roomate to get home so I can use his car to go buy a light. Im afraid to drive it up to the parts store. Don't want to end up stuck on the side of the road. It's been running really good for the last 3 months untill it started this a few days ago. I'll see if I can pick up a gauge to check the psi from the fuel pump. Do you think a bad fuel pump could cause this?

[geezer#99]

Not likely the fuel pump.
To check to see if it's flooding, warm it up good then look inside the carb with a flashlight and look for any raw fuel. If there is some then you know it's flooding a bit.
You could of got some trash in the needle/seat too or you got a bad batch of gas.
Do you always buy gas at the same place?
Did you fill up a few days ago?

[kelz702]

Originally Posted by geezer#99

Not likely the fuel pump.
To check to see if it's flooding, warm it up good then look inside the carb with a flashlight and look for any raw fuel. If there is some then you know it's flooding a bit.
You could of got some trash in the needle/seat too or you got a bad batch of gas.
Do you always buy gas at the same place?
Did you fill up a few days ago?

I'll go out and warm it up right now to check for raw fuel. There's 2 different places I usually fill up at. Chevron and Shell up the street. I filled up yesterday and a few days before that.
How do I check the needle/seat for trash? I don't have very much experience working with the carb. I'm always afraid I'm gonna mess things up worse if I start tinkering with it.Haha

[kelz702]

I warmed it up and notice a little bit of raw gas in the carb. Not a lot though. I also noticed that the power wire for the electronic choke wasn't hooked up. A few weeks ago someone got into my truck and ripped out some of the wires under the I dash. I hooked it back up and the choke opens like its supposed to. I was hoping that was my problem but its not. It's still running the same.

[geezer#99]

You might need a regulator. Here's one at Summit that I've used. It only goes to 6psi which would work for you. Your local autoparts store could get you one. It doesn't come with a gauge but you could plumb one in after the regulator.
http://www.summitracing.com/parts/mrg-9710/overview/

One trick to check if it's actually too much fuel pressure is to squeeze the fuel line hose off (pliers work) and see if it quits leaking. And when you release the pressure the extra flow will clean out the needle/ seat too.

[So.Cal.Super]

is it a mechanical fuel pump? and is your filter after or before the pump?

[kelz702]

Originally Posted by So.Cal.Super

is it a mechanical fuel pump? and is your filter after or before the pump?

Its a mechanical fuel pump. The filter is after the fuel pump.

[kelz702]

Originally Posted by geezer#99

You might need a regulator. Here's one at Summit that I've used. It only goes to 6psi which would work for you. Your local autoparts store could get you one. It doesn't come with a gauge but you could plumb one in after the regulator.
http://www.summitracing.com/parts/mrg-9710/overview/

One trick to check if it's actually too much fuel pressure is to squeeze the fuel line hose off (pliers work) and see if it quits leaking. And when you release the pressure the extra flow will clean out the needle/ seat too.

I'm gonna go pick up a regulator and a gauge tomorrow morning. I starting driving it up to auto part store and its acting up a lot more often. It was just bogging down when i punched it, now it almost the whole time. I tried your suggestion with the hose but it didn't seem to do much. I pinched it off before the filter and I could still see gas running threw it lime it wasnt pinched off.
I really appreciate your help and the suggestions.

[bigmac73]

i would do the flashlight test, with the truck running look down the carb with a flashlight and see if you see any fuel or a fine mist or some sputtering , if is is spitting or there is a drip your idle mixture circuit is clogged with trash, you should not really see any fuel , maybe a fine annular ring if anything

[kelz702]

Originally Posted by bigmac73

i would do the flashlight test, with the truck running look down the carb with a flashlight and see if you see any fuel or a fine mist or some sputtering , if is is spitting or there is a drip your idle mixture circuit is clogged with trash, you should not really see any fuel , maybe a fine annular ring if anything

Thanks for replying bigmac. I just checked it with a flashlight and didn't really see any extra fuel. I've been thinking about attempting to top of the carb off to check the needle and seats. I've watched some YouTube videos and I believe instructions come with the rebuild kit. It sucks because I just bought this carb new a year ago.

[bigmac73]

have you checked the edlebrock web site for tech support, i had a 1407 (i think)on a dodge 440 that had a real bad hesitation/stumble, followed all the recommendation, changed out the different metering rods, and springs ect ect, i never could get it working right, but they at least tried to assist me .

and it was new out of the box, i finally gave up and got me a 850 double pumper Holley after that,

[bigmac73]

also check the total advance,
rev it up to around 3000 RPM and see what the total timing is at? 34-36 deg at 3000 rpm is a good setting , some people say 3500 but mine stops at 3000

you will need a good light with adjustments for advance on it , so you can manipulate the light. so at 3000rpm adjust the light so the timing tab and mark are at zero then look at the read out on the light that should give you the timing or you can do it backwards set your timing light at 34 deg BTDC and rev it up then check the timing pointer/tab the mark on the balancer should be around 0 somewhere , you will have to figure it out a little and go from there

my engine is set at 16-17 BTDC initial and total over all 36 Deg, I have a vac advance limit bracket to 4-5 degs on it

so you figure your initial is 16 and your mechanical adv is 20 = 36 plus what ever you vac advance adds