The old victa 85cc (and 170cc) use a condenser of 0.27-0.23uF (where the u represents Greek mu, symbol for micro, giving microFarads)
The 125 and 160cc use a condensor of 1.65-1.80uF but may also have the electronic system (breakerless)
From Gregory's Small engines service and repair manual... Whee, it's already coming in useful!
You may be able to measure the capacitance with an appropriate multimeter. I'm guessing an incorrect condensor, if it allows a proper spark at all, will adversely affect the timing.
Hope this helps,
