noob needs help! Truck stumbles to death

[OldBluef100]

Hi i have a 400m in my 68 f100, everything is newer in it besides a few things, it has a small knock in the driver side b/c one of the washers under the rocker arm shatter but anyways. I just spent an ASS ton of money on my truck going thew it and for some reason I will drive my truck around for a day and it will act likes its fine. Then out of no where it will just stumble to death and it wont want to start and i have to put the gas pedal to the floor to start it. Now it just starts up and sputters to death. I just had my holley 4150 fully rebuilt , newer fuel pump and filter. Choke isnt getting stuck on at all. could anyone shoot me some ideas on what else i should be checking? Anything helps thanks!

[Ranchero50]

With the little amount of info you've given the best guess is carb flooding out (needle valve leaking by) since you have to floor it to clear the flooded condition to start it. I'd start there. Run it a bit, shut it off and look down the venturi's to see if it's dripping fuel into the bores.

Jamie

[OldBluef100]

Ok thanks i will start wit that, if its flooded wood the carb make a noise , i hear a very odd noise that i swear is coming from the carb

[sideoilerfe]

Take the 400 out and throw it in the trash and replace it with an FE.

[OldBluef100]

Ya right this 400 puts those fe's to shame anyday , i just got back my truck from a shop that had no clue what they where doing thats the problem

[willowbilly3]

400s are really not that popular here and FEs are. Lots of people here will help you anyway but don't shoot yourself in the foot with the 400s better than 390 stuff, it's pointless. Just take the ribbing in stride.
OK, you have float level plugs in the float bowls. If the carb was benched by someone else then they could only guess at float level and you need to check/adjust it. You might need a fuel pressure regulator, you don't need more than about 3.5 psi on a street engine. Also check for fuel lines sucking air.
You have a broken valve train component but are driving it with it making noise? Better give that attention before you go any further. I am not sure why there would be a washer under the rocker arm???
My bet is you have more issues here than carb problems.

[OldBluef100]

its leaking in gas after i shut off the vehicle, and its just ready to pour out of the carb thier is so much. Would that be something that needed to be replaced or just tuned? And i had it proffesinally rebuilt at a "performance shop". and what is knocking is on my driver side valve its one set up, and the whole rocker arm assembly is called "Fulcrum" or somethin like it and in that assembly thiers a special washer , i cant rember where it goes exactly buts its somewhere in thioer and it was shattered and now it knocks. But yes i know its not good thats why i parked my truck for now

[Johnm]

i had a truck that did that back in the day and it ended up being that the fuel lines were all gunked up.


FE forever

[MaxKlinger]

When the problem occurs, have you verified that you're getting spark? Nothing worse that a wild goose chase in the fuel system when you have an intermittent ignition system problem.

[OldBluef100]

fuel lines are new..i think its the float in the carb..either the shop didnt put somethin back together right or a part went bad . My plugs are probably fouled to all hell now but they fire...i want to thank everyone for the help and input on this.

[willowbilly3]

Also if you have Champion plugs in it throw them away and get Autolites.

[fomocoguy]

You can check the float level by pulling the sight plugs on the sides of your float bowls. It's the big brass screw head. Run the truck and then shut it off. Pull the plug; if gas pours out than either the float or needle is bad, or the float is just adjusted too high. On the top of the carb is the float adjustment. To do this you loosen the brass screw head (similar to the sight plug screw in looks) and spin the nut underneath it to adjust the float up or down. If the level is too high, you will spin the nut clockwise to lower the level. It is generally good to do this while the vehicle is running, but do the first checks with it shut off in case gas pours out all over. Adjust the float down some, then start it, rev it a few times, shut it off, and recheck. When adjusted properly you should be able to pull the plug and have no gas come out while the vehicle is idleing. Then if you rock the front end a tad you should see a little come out, indicating that the fuel level is right at the bottom edge of the hole. Hope this helps!