1968 cranks but won’t start

[Sundevil00]

Rebuilt 302 dropped into 1968 Mustang. Everything under the hood is new except the Edelbrock 1406 carb. Fuel is being sent to the carb and there is spark. Timing is set at 6° from TDC. I just cannot get it to finally start. Any suggestions?

 

[08GT500]

Rebuilt 302 dropped into 1968 Mustang. Everything under the hood is new except the Edelbrock 1406 carb. Fuel is being sent to the carb and there is spark. Timing is set at 6° from TDC. I just cannot get it to finally start. Any suggestions?

Hi,
68’- sweet!
The Edelbrock carb, should be rebuilt on a fresh motor. Any fuel left inside turns to a white shellac that clogs tiny offices crucial to the Carb’s operation.
It, like it’s grandfather the Carter AFB, and Holleys, Quadrajets, and all Carbs of this type have (at least) one accelerator pump that you can see if you open the choke plate, look at the 2 primary venturi’s(Barrels), there’s a squirter that’s shoots fuel into both as the throttle is opened. If it doesn’t squirt, either the fuel isn’t reaching the float bowls, the float’s needle & seat is stuck-not allowing fuel to enter, or the accelerator pump needs to be replaced.
Test the theory, add half a Dixie cup of fuel to the 2 primary venturi’s, or a 2 second blast of Ether & see if she fires. Put the air cleaner on so if it belches flame it puts itself out.(Carb’s like to keep you on your toes). I’ve lost my eyebrows more than once, lol!
If it fires and dies, seemingly running only off the Ether, you may not have fuel in the Carb. Move the throttle again by hand, any squirt yet? If no, the Carb needs some work- it’s simple.
This Squirt of fuel is necessary for the motor to come to life so vacuum can begin pulling air by the Carb’s Venturi’s & fuel is drawn into the stream normally. The Choke closed causes less air to enter, vacuum pulls more fuel from the Carb Venturi’s.
Accelerator pump always squirts when the throttle is moved. When starting, a few pumps of the pedal is imperative.
Running a Mechanical or electric Choke?
Timing. The combustion stroke when the engine’s #1 cylinders piston is at the top of the Cylinder when the balancer pointer is at 0, both valves are closed, Distributor rotor should be pointed at the #1 Cylinder’s plug wire position on the cap. The other cylinders follow the CCW direction of Rotor rotation & are landed on the Cap in the firing order used. There’s two, depending on the Cam being run.
If you’re running a 302/351 HO Cam, you’ll run the HO firing order. If a non HO Cam, the non HO firing order.
HO Firing order: 1-3-7-2-6-5-4-8
Non HO Firing order: 1-5-4-2-6-3-7-8
Triple check your plug wire locations on the Cap and the motor, and CCW rotation direction of the Rotor, and where number 1 cylinder is on the Combustion stroke, Both valves again, will be closed on the Combustion stroke.
Cylinders, starting from front of Car, passenger side..1-2-3-4
Same view, Drivers side..5-6-7-8
Get it wrong with a Carb and expect flames and exhaust backfires. Keep a wet towel close and a fire extinguisher nearby, just in case. 95% of Carb fires put themselves out within a few seconds.
No big deal. But be ready.
Have a timing light, a wrench to tighten down the Dizzy nearby so you can accurately time the motor once it fires & adjust the idle screw by hand to keep it running on its own.
Mark 0, 5, 10, 12 Degrees in different colors on the balancer so you can see them when timing with the light.
Keep the Dizzy a bit loose so you can move it while running, time it, lock it down.
I don’t know what the motor is running for a Cam, fuel pump, Dizzy, etc. Running points, a Crank trigger, or an electronic Dizzy.
A little more info will greatly help me help you get this running right. A few Pic’s will help greatly.
You’re running 6 Degrees of Spark advance? ATDC or BTDC?
If you’re running a flat tappet Cam (Solid or Hydraulic)it must be broken in, first 20 minutes of startup are crucial. A Roller Cam does not require the same degree of attention here.
Did you prime the oil pump to get oil everywhere before attempting to start?
If no, pull the Dizzy after marking with the cap off, mark where the rotor pointed on the Dizzy, spin the pump with a cordless drill, Hex bit on the end.
Have a helper view the oil pressure gauge as you prime, if you don’t have a Mechanical gauge, I’d strongly suggest getting one. 25$ & 15 minutes, and a mechanical temp gauge, both are the most important vitals to monitor now.
I put a set in the engine compartment, so I can keep an eye on things while tweaking things. Can just tape them there to watch them, fully install inside later. Up to you.
Let me know if you have any questions, and what occurs. Happy to help!
Best!
John