Nut size for tensioner pulley - KAD300

[alt]

Hi all,
I didn't have a caliper with me at the boat.... one of the nuts on the tensioner pulley (the 15mm head that you tighten, to tighten the pulley) could do with replacing.

It's a flange nut.

Does anyone know what thread size i'm looking for?

I also need to replace the washers on the top bolt of the alternator.... anyone any idea what size washers I need here? The heads on the nut / bolt are 16mm.

A very particular question I know, apologies! Thanks for any assistance you can provide.

 

[aerobat]

Don,t take my answer as "100% sure" but l recently changed the tensioner pulley on my '44 and the tread itself looked like an ordinary metric m10 . That said i cannot comment on the tread pitch for sure ( but do not think its something special ) and the flange of the nut might be specific so if i were you i would give a volvo penta dealer a quick call if you can get an OEM one . Other option is to take the old to a local hardware strore and simply compare it to the sortiment there.

Hope this helps a bit