Lister D Governer springs and linkage - new springs far softer than old..

I had a problem where the governer was constantly making the carb throttle open/close all the time... but so I have replaced the spring at the top, and the little adjuster hook, and also replaced the springs in the governer....(for supposed 1000rpm ones as how mine should be.)

Anyway, to cut a long story short, it now runs perfectly smooth when up to temperature, and when left under load from the pump..(pumping water out the water butt... and pressurised back into the same water butt...) it warmed up perfectly, ran perfectly smooth, and visually seemed a bit faster than what it was before...(also for some reason the pump made less strange oscilating noises than it did before..)

but, thats not what I am worried about... the old springs that came out appeared "original" but were far stiffer than the new "1000rpm" ones

when attaching old and new together on the bench, and stretching them apart, the new one extended several mm before the "old" one actually even started to extend..

this does not make sense... as in theory having softer springs would make it run a lot slower...

anyway, my next task is to put a tacho (ie strobe tacho) on it somehow, as I now want to confirm that it really is running at 1000rpm..

the only thing that I can spot is that when I removed the old springs, the split pins did not look original, ie two were bent right over like you would expect, but the other two had been clearly "touched" by someone in the past as one was not even bent apart properly.