Can you order overhaul kits for my TAMD41A and TAMD41B?

I quoted you OEM directly from Volvo Penta one for the A and one for the B.
When we do this, we almost always rebuild the A into a B.   You reduce the smoke
substantially and the engine runs smoother.   You do need to change the fuel injection
pump settings and the injector tips (around $950 or so do both), but it is very much
worth it.

There are a couple of companies offering aftermarket versions for the TAMD41P-A
but not for the A and B versions.   We have not had much luck with the aftermarket version
as they are pretty cheap.