Steve,

I checked, it's not a Bosch part, it comes from an Italian firm.

The parts shop couldn't direct me to the source.

I'll put an inquiry onto the German site where I first got the hint, and shall replicate this thread in the "Vintage Mercedes" forum, where it probably belongs.

It's really a tip for clapped out old motors with no compression, that I have a habit of owning.

As far as burning out the motor quicker, I was flattening batteries in cold weather before, now it's Brrrrrroooooommmm!!!, on the first couple of turns.

If you know anyone who can speak Italian, get them to type "nine volt start motor" into a search engine and see what they come up with.

__________________
306D 1975 (camper) - rusting away
W116 450 SEL 1975 - sold
W114 long wheelbase ambulance, 3 litre diesel 1974

VW Golf 1 convertable - midlife crisis item
VW T4 van - support vehicle