1f running rough under load (1 Viewer)

[Fj40owen]

Needing help with rough running 40.
This one is a 3 on the tree 1f with oem carb.
Carb has been cleaned with new gaskets. Verified no vacuum leaks.
Timing is set at 7*

Starts and runs fine, but when pedal is pinned to the floor it bogs, but regains power if only about 3/4 pressed.
Will also mention some black smoke on hills while bogging.

Odd thing is that there is no adjustment at the air/fuel screw (valve cover side)
All the way in Runs the same as 4 turns out.
The speed idle screw is responsive

Any ideas?

 

[anothernz45]

Air filter?

 

[Fj40owen]

Air filter?

Clean

 

[Pighead]

What altitude?

 

[rlong]

Check for vacuum leaks.. if the idle screw makes no difference there is almost always a vacuum leak somewhere!

 

[Fj40owen]

What altitude?

7200 ft. Was not having this issue for years until the start of summer.

 

[anothernz45]

Wind more advance on

 

[cruisermatt]

How are the distributor shaft bushings?

 

[Fj40owen]

How are the distributor shaft bushings?

Tell me more about that

 

[cruisermatt]

Tell me more about that

How about you check them and report back?

 

[Fj40owen]

How about you check them and report back?

It would be more helpful if you provided a brief explanation of what to look for there. Geez

 

[pb4ugo]

I think he's asking if the distributor shaft doesn't wobble. Also make sure the mechanical advance is working. You should be able slightly twist the rotor and it should snap back when you let go. Make sure the vacuum advance canister isnt leaking, by sucking on the vacuum line going to it.

Edit: snap back, not stop

 

[Fj40owen]

I think he's asking if the distributor shaft doesn't wobble. Also make sure the mechanical advance is working. You should be able slightly twist the rotor and it should snap back when you let go. Make sure the vacuum advance canister isnt leaking, by sucking on the vacuum line going to it.

Edit: snap back, not stop

Thank you

 

[charliemeyer007]

Try pushing side ways on the rotor bug towards/away from the engine and then towards/away from the the front bumper. There should be very little play. If it has mechanical advance the rotor bug will rotate a little in one direction and will snap back when released.