This probably won't help those of you who have Westerbeke engines, but it will help Universal engine owners.
I finally figured out which Kubota tractor uses the v1902 engine that Universal calls the 5444/M50.
It's the R400 Loader.
Attached is a list of tractor models and their block numbers
There are two v1902 engines, Direct Injection (v1902-DI) and Indirect Injection (v1902 or v1902-IDI). The 1980s Universal 5444/M50 like the one in my 1982 boat is the v1902 IDI.
So who cares, right? We all know at Dnnnn or Vnnnn block number we have, but that is not enough.
The problem is when you go to Kubota looking for a part, the first thing they ask is what tractor model you have; that's their starting point for parts searches. Whether they can't or won't search any other way is unknown. (https://apps.kubotausa.com/illustrated-parts). It doesn't do any good to tell them it's a v1902, they can't find anything with that info.
Thanks to the folks at OrangeTractorTalks for telling me what I have and linking to the model cross reference file (see attached file).
http://www.orangetractortalks.com/forums/showthread.php?p=164748
I've tested this relationship by buying several parts and they all fit, some even better than the original (injectors, glow plugs, bleed valve, high pressure lines from inj. pump to injectors, including several hoses and copper gaskets).
All I did was tell them the tractor model R400 Loader, described my part or showed them the old one and they looked it up. Ordered and received within 2 - 3 days at the store, no long waits, no outrageous prices, and no shipping (had to pick up at store). Prices at the local dealer were often lower (when shipping factored in) than online sources. Boy am I glad Pearson put a tractor in my boat!!
Sometimes with boat stuff we have to pay high price because of low volume, marine quality, blah, blah, blah, whatever. I just can't fathom paying nearly $2000 for the exact same injection pump that costs ~$650 at a tractor store or $50 for a $10 glow plug. That's just insane!
Take a look at tractor model cross reference and pop open a new thread at orangetractortalks for help; those folks are real nice.
http://bodylens.com/boat/KubotaModel-enginecrossReference.pdf