Probably normal, since a piston fires every 90 degrees of crankshaft rotation. Here’s the best I could find for firing order:
The three on compression should be in order in the firing order, i.e., 4-3-6, etc.
I have to move the throttle very slowly in order for it to rev, and yes i would like to reach redline
In the case of that picture, 1,3, and 7 were all in compression at the same time.
Do you think it is just really bad carb tuning?
Puzzling…all I can suggest is pulling the plugs and distributor cap and verifying the correct firing order and valve movement. Mark the plug wires before removing to be sure to keep them straight. Mis-routed plug wires is a common problem. (My diagram could be the wrong one for your engine.) Is the firing order shown on the block anywhere?
Two more ideas:
Check timing mark on harmonic balancer…it may have shifted.
If everything looks perfect, try moving distributor one tooth each way.
The 1 and 8 cylinders are in the right places
How are you determining TDC? The best way is a thin rod through the spark plug hole feeling for the piston. If you can see the top of the piston, that works also.
Is the engine an AMC?
From the reports here, the most common reasons why an engine won’t increase rpms from idle like it normally should as you push on the gas pedal are from among
- intake air restriction (air filter clogged, birds nest in air intake path)
- fuel supply restriction (fuel filter clogged, fuel pump bad, carb (or fuel injection) problem)
- exhaust restriction (cat clogged, muffler clogged)
- ignition or ignition timing problem (weak spark, spark plugs, hv wires, coil, distributor cap/rotor , distributor)
- egr problem (sticking, opening too wide, or too soon)
If I had this problem on my truck here’s the order of tasks I’d do to try to diagnose/fix it
- Secure aftermarket repair manual (including wiring diagrams) and read the tune-up section thoroughly
- Bring all routine engine maintenance up to date (new plugs, hv wires, dist cap/rotor, air filter, fuel filter, oil, oil filter)
- Verify healthy spark at spark plug
- Verify base ignition timing (should be appx 6-8 deg BTDC probably)
- Verify ignition timing advances smoothly with rpm. Max advance should be appx 25-35 deg at higher rpm
- Complete vacuum system check
- Check for obstructions, & clean out all debris from intake air path
- Measure fuel pump volume/minute output.
- Check carb’s fuel level
- Check for any obvious exhaust restrictions (visual, intake manifold vacuum test)
- Verify EGR operation
- Compression test
- Rebuild carb (including setting choke, fast idle, curb idle, and mixture)
- Remove/bypass cat and muffler as a test for non-obvious exhaust restriction
The accelerator pump may not be working, check the operation of the accelerator pump in the carburetor.