86 f150 300/factory 1bbl np435 granny tranny. Feedback doesnt work

Ive got the truck running very well. My question is, when i floor it in 3rd at about 1000rpm/20mph ( no tach) it bogs down and jerks until the rpms come up to around 13/1400. Now i know its a bit slow and high of gear to be doing this regularly, im just looking to get the base mixture set to where it will just pull on up from here steadily. Should i lean it out more or fatten it up more. Again it runs very well right now. Timing is a fixed 10* right now, idle is decent, a bit high but acceptable for now. Plugs and all are fine and all cylinders fire.

Before the change your ignition and stuff gets thrown out, i know this and will be doing so in about 2 months when taxes come back so i have enough cash to justify spending the $400 bucks for parts.

I havent messed with carbs for a few years before i got this truck.

 

Probably too lean. Fat/rich usually doesn't bog unless really fat. But, it could be ignition as you are raising cylinder pressure dramatically and that means the spark doesn't want to go across the gap, and will find any short cut that it can - like jumping through the insulation of a poor plug wire or to another cylinder in a dizzy cap that's in bad shape.

 

Yeah, i know the ignition being fixed isnt helping. Ill try another 1/4 or so out and see how that does it.

I appreciate the help. My engine moves so much air (exhaust is quiet as far as a rumble goes) i cant hear pinging. Honestly im not sure ive ever heard it. Im going to get a vac gage as well when i change ignitions. Im wondering if maybe ill do a permanent guage in the cab. Im gonna do a 2-1/2 or 4" tach clamped on my column infront of where the tach should be. Might add in a oil and temp with the vac. Smooth the dash speaker hole and mount it right above my stereo.

Do they have aftermarket fuel gages as well? I could cut out my bezel and use aluminum and build a all new cluster. Idunno
Anyway thanks for the advice!

 

Yes, they have aftermarket every gauge. Good luck!

 

At 1000 rpm your idle circuit is not doing much of anything. Try it, you are close to being at the idle circuit, but don't be surprised if it doesn't do anything.

I agree with Gary it may be a ignition problem. Only other thing it could be is a accelerator pump problem in the carb. A carb works like a paint spray gun. The air flowing through the gun picks the paint up out of the cup. The carb works the same way, air flowing through it to the engine picks the fuel up out of the fuel bowl. The more airflow, the more fuel is picked up.

What happens when you nail the throttle? The engine is now sitting there demanding lots of fuel, but the carb can't give it any because you are only turning 1000 rpm. Fuel is added by airflow, but there is not that much at 1000 rpm. So you get a bog and you have to wait for the engine to slowly pick up rpm, so the airflow can slowly rise and add more fuel.

What they did to get around this is add the accelerator pump. It does not depend on airflow to add fuel to the engine. It mechanically pumps fuel into the engine. It gives the engine the fuel it needs when there is a big change in fuel demand and the airflow is not there to support it.

You can pull the aircleaner off, and with the engine off, look down the carb throat and watch the accelerator pump work. You should get a strong stream of fuel the instant you push on the throttle. If you do, I would work on the ignition system first.