Skip On Cyl 4

Ted had a skip today so I started pulling plug wires. Found out it was cylinder number 4. Pulled the plug and it didn’t look fouled. I did a compression check to make sure that I didn’t burn a valve like it had done once before. That was good. I swapped the plug out and no change. Took the cap off and all the electrodes were pretty corroded. Put a new one on and still no change. Pulled the plug out and then started it. There was a very weak spark. Pulled the cap and dust cover off and to check the point gap. There wasn’t any. Readjusted those and problem solved!

Just thought this might help someone in the future. It’s amazing how these Flathead 4s can run on 3 cylinders with no point gap.

 

Yeah, you need dwell for the coil to recharge. Maybe #4 has the longest wire with the most resistance?

Would suspect that your coil is not so great.

 

Example why the old saying was that logical diagnosis depended on first tuning to specifications.

 

Coil is a Petronix flamethrower and isn't that old.

 

...and?

 

Never rule out bad plug wire unless you test them (run an Ohms test)