Sputtering

[massillon preacher]

Out of the blue engine sputtering today, will sputter for just a little bit then run fine for little bit, then back to sputtering, sound like fuel filter? Or any other thoughts? 71 F100 390

[Ren]

Weak fuel pump can cause that too. Check with a pressure gauge. I think less than 4 psi is suspect.

[massillon preacher]

I replaced filter today and used clear one so I could see fuel, if it was fuel pump wouldn't I have seen no fuel in the filter or could it just be now enough pressure to feed carb properly. It is worse today now, even at idle it is spuddering. It was running tops one day and the next start up a couple days later this issue. Hit the gas and it sounds like sucking air in and spudders. Anymore ideas.

[Ren]

"As ye seek, so shall ye find." As a preacher, that should sound familiar.

Sometimes there's a little screen filter to be found when you unscrew the fuel line at the carb. Most folks say to get rid of it.

What you're describing sounds exactly like fuel starvation to me.

A 'weak' but not 'failed' fuel pump or a restriction in the fuel system. Check the fuel level in the carb. That can be learned by checking the archives.

[sargentrs]

Have you checked for vacuum leaks?

[massillon preacher]

I did a quick check with Carb Cleaner spray and didn't find anything. I do now after a few starts notice rusty sediment in the new fuel filter I put on as first try to fix. It is actually getting worse, as per the first day it would sputter on take off and seem to catch and go until next start from stop sign, now after a couple more days, it will start okay right off but within a few seconds it sputters off. Each time I try to restart, it seems to get worse by sputtering off quicker and quicker and it gets harder to restart as well. Buddy says to just take off carb and rebuild it, some say it is probably the fuel pump although with the new fuel filter I can see gas clearly going through to carb, filter is completely filled with fuel, sediment bothering me though that I see makes me want to believe the carb is not getting all it should, not a lot of sediment but its brand new filter after a couple days. The only thing that I did to it from the day I bought it when it was running PERFECT to a few days later was add oil, it was low, put $10 of gas in it and add coolant. The gas tank does as well have the float broke off inside rattling around as well, i mention just to have all things out there. I took cap off and looked at points, looks like that was done not to long ago, all pretty and clean inside. The thing that is throwing me is just how perfect it was running then out of blew not good at all. It really makes me think it has something clogging carb, seems odd to just go from great to bad but again been a while since i had a old vehicle like this. Also when I put gas in without thinking I put the cheapest in as I usually do for my new car, not sure what was already in it as well. Please help with anything you can think of, want to drive my truck. I'm sure you all know a truck setting in garage is UGLY sight. LOL

[sargentrs]

A carb rebuild is cheap and pretty easy. Crack it open n see what's in there.

[massillon preacher]

Okay we see the problem just don't understand why. My buddy came over tonight and we hit the key it starts like usual and then dies off after a little as its been doing. We got a mirror out and notice first that even when the truck was off, the bowl was filling up with gas, a good bit, then we would start it and it would burn that fuel and the bowl would go dry and that is why it would shut off, after shutting off again bowl would the begin to be filled up with gas again. Basically with truck off hit throttle and nice steam of gas, start truck runs till it burns gas but doesn't seem to keep producing gas in bowl while running. What do you think about this?

[massillon preacher]

Well folks we finally got her and it was a combination of things but not sure which was the worse of it all. Way back when it first started sputtering after running fine one day and not the next, the first thing I did was change fuel filter, no fix. Then I seen the Holley carb was actually still squirting gas in even after it was shut off so carb rebuild was done, no change and actually seemed worse. Then I went and bought new Holley and it was slightly better but still sputtering and shutting off. I checked fuel pump it was fine, set carb up with every possible fuel to air mixture, checked idle and nothing worked so then I began to think it might be tank passing junk up to carb or just clogging but before I did check that I finally listened to my nephew whom told to me to check this a while back but I was stubborn thinking because it ran fine one day and next not it couldn't be these obvious things. The plugs where all fouled up and the points desperately needed cleaning, ah ha and one last thing, couldn't believe it, in the fuel line was a "Helicopter leaf" LOL that's what I call it, someone told me its a maple leaf. I call it helicopter leaf because it spins around like a helicopter as it falls from tree. No idea how it got there and mind you I just bought the truck a month or so ago. Because it has a non stock gas cap that loosely fits on I was guessing prior owner may lost cap and didn't replace right away and it fell into tank, who knows but after the points, plugs and removal of clogged fuel line, purrs just like the day I bought it a few odd weeks ago, HAPPY TRUCK MAN again I am.

[sargentrs]

Glad to hear you figured it out!