sputtering redux

[nevets]

Just a follow up on my previous post. As before, the car runs smooth and strong under acceleration but sputters/misses at a constant RPM, as when cruising in 3rd or 4th.

Things I’ve done: New points, plugs, condenser, rotor, and coil. Adjusted timing with timing light and it appears to be ok. Difficult to determine if it’s ignition related or carburetor related. Pulled a few plugs to judge whether it’s running rich or lean but after only 20 miles of driving, plugs are too new to tell a story. They are definitely not sooty or oily.

Watched the engine idle in a very dark garage and saw no arcing around dist cap or plug wires.

One thing I noticed is that the fabric insulation is frayed on the thin black wire inside the dist, not the ground wire, the other one. Sorry for being so vague in my terminology. And there is no felt oil plug in the top shaft, which there should be, according to NN’s tech briefs. My next step is to replace this wire and attempt to lightly lube the dist per the manual. Perhaps replace all the HT wires as well.

If the car is running too lean as someone suggested, could I test this theory by simply driving the car with the choke out slightly?

Any additional thoughts would be appreciated, thanks

 

[GregW]

If the car is running too lean as someone suggested, could I test this theory by simply driving the car with the choke out slightly?

That's a trick I use on my motorcycle. If the engine runs better with the choke, it is lean.

 

[nevets]

Thanks Greg. I was holding off responding, hoping there would be a few more comments or suggestions. I guess this issue is either one that no one else has experienced or there are just too many variables to make a diagnosis. I will plod through all the easy stuff and report back on my progress. I'm still thinking ignition.

 

[nevets]

A quick update...I checked the point gap and it was too wide. After adjusting the points, the car is running noticeably smoother.