SP5B Weighting
After some minor tweaks, my 12-day clock ran for 2+ weeks including a winding or two and was keeping excellent time. It's using 4.4 kg of weight with the fishing line loop as designed. Although the weight is a touch heavy, I was just happy it was running so well. Then I woke up one morning and it had stopped. I was able to get it to run again for anywhere from minutes to hours by making minor adjustments but then it would stop.
I took the fishing line loop out and suspended 2.2 kg directly planning to run it without the escapement but before I could do that, it's back to running like a champ again--16 hours straight. I tried the loop with 4.4 kg and it stopped again. As I write this, it's running great with 2.2 kg direct hang.
Any ideas what could be going on?

If the clock works with 2.2kg direct and stops with 4.4kg plus a pulley, and nothing else changed, then the pulley must be the problem. More likely, something else changed. It is easy to check the pulley just in case.
Two things to check after the clock stops are the escapement and the pendulum. It's even better if you can observe the clock just before it stops. Does the pendulum slowly lose amplitude? Or is the escapement losing energy?
Move the pendulum back and forth slowly while observing the escapement. Does it have the same energy as before? Then check the beat. Does the escapement tick and tock at equal amplitudes from side to side?
This clock has a friction sensitivity with gear 3 and the escapement. Sometimes when the clock is being adjusted, the frame can be squeezed and the escapement shaft collars get moved. This can push against the escapement. The slightest amount of side thrust against the escapement can stop the clock.
Hopefully, this provides some help.