So here is the inside of the Clarke 160EN . There is an inductor, bottom left of the pic. But there is absolutely no space. Even on the other side of the panel where the spool is.
Yes, that is a bit tight in there. The cables to and from the capacitors need to be thick and short, so adding them externally would not be good.
One 47,000 uF may squeeze in on the spool side, under the wirefeed assembly, or 3 x 6,000 standing in a line next to the rectifier.
There is no space next to the rectifier I'm afraid. I should of looked for markings to see how many amps that motor draws today when i had the cover off. Anyone know off the top of their head??