I have owned engines from almost all of them and currently have a Westerbeke/Mitsubishi. I would not buy another Westerbeke or Universal engine as I find the marinization awkward at best and parts channel & pricing rather insane.. The base Kubota or Mitsubishi blocks that Weterbeke uses are fine but they really lag behind the others in many ways.
Yanmar's are great engines but I really have grown to dislike their extremely closed off & very exclusive dealer network requiring you to buy within your "zone" etc. and the parts prices have become as offensive as Volvo & Westerbeke... How about $679.00 for a Yanmar "Made by VDO" tachometer that is a proprietary fit for the Yanmar engine panel.
Also the newer engines are starting to come through "electronic" which you really do not want. Get an old-school engine as soon as you can because they will be gone pretty soon, even on smaller blocks....
If I were re-powering my own vessel today, hands down, it would be Beta. Their marinizing is excellent, base block is Kubota and they spend a good deal of money carefully balancing each flywheel to make the engines smooth enough for use on boats (as opposed to tractors or industrial equipment), something Universal/Westerbeke ignore and makes a differnce especially on three cylinder engines..
Beta also does not have
contracts with the base engine suppliers that specifically prohibit them from selling parts for a Westerbeke or Universal "marine engine". I was able to get a Mitsubishi parts manual but it entailed some serious sleuthing as Westerbeke removes the original engine serial number which one would need to get a parts manual from a Mitsubishi distributor. The minute you even mention Westerbeke they will end the conversation. Some parts through Westerbeke have been a 20X markup over direct from an industrial supplier! In order to buy the manual I had to tell the guy
"Well its a red colored engine but it came in a home built wood chipper I bought. All I know is that it is a Mitsubishi SL42 engine block.".... That is really pretty offensive...
On the flip side of that Stanley at Beta will tell you the exact Kubota part number you need and you can then source it at any tractor re-seller for the most reasonable price you can find. Over the life of an engine this could really add up to a huge savings. Only the marinized parts need to come from Beta and even some of those are "sourced" parts.
Beta also serves up serpentine belts as standard equipment on most engines making a performance alternator upgrade possible while Universal/Westerbeke & Yanmar are still in the dark ages & still using v-belts.
Heck right on the Beta site they will say
Beta 20 (D722) the "D722" is the Kubota block.. Beta does not hide this from you. Go ahead ask Yanmar which block it is that is shared with a John Deer or other tractor? They WILL NOT TELL YOU. Yes Yanmar marinizes their own engines, but this does NOT make them a specifically built "marine engine". They are still the same as the industrial or tractor engines & identical to the blocks they sell to John Deer etc.. BTW I buy many Yanmar parts from John Deer & other dealers for a LOT LESS than Mack Boring.
Do not get hung up on the alternators as NONE of them are do much on deeply cycled banks. If you desire any level of
charging performance take the smallest alt they provide and then convert it to a high performance alt with external regulation.
