Engines and Choices and Advice, Oh My
On this and your related thread here you are getting good advice. Real. Good. Advice.
Having never owned an inboard gasoline auxiliary, I have no helpful words...
But, regarding the "siren song" of being attracted to changing to a diesel, I might have a thought or two. If you read my blog here you will see that last year I removed my '88 model Universal diesel and replaced it with a new engine. Investing (oops, wrong word!) about 15K total in this project made sense for us because we have owned this boat since 1994, and have
no immediate plans to sell it.
I had to learn basic engine trouble shooting very early on, but have never become more than an opinionated parts changer.
I do all of my routine maintenance.
About the allure of that 'siren song'..... you will, in moments of stress, wander across used small diesels for sale. Most anything at about 20 hp to about 25 hp will do the job. You might find one that appears to have a lot of life left in it, and, after going thru the whole install gauntlet of new beds, new fuel system, new instrument panel, and probably replacing a bunch of electrical stuff "while you are there", you will end up with an engine that only burns about a quart of lube oil a season, and only has a few leaks and blow-by residue.
(That is a quick description of the fine-running 23 hp engine I removed. I could have sold it for a quick 1K, but instead gave to a friend who is rebuilding it to repower another boat. And then there is the problem sorting out the used engines by reputation and modern-day parts availability. :0
So, hang in there and keep us posted.
In the dept of "unsolicited advice" I would also say that over the years I have received invaluable help from the other sailors in my yacht club. If you are not a YC member, you might want to check around for a club geared to DIY owners. (i.e. not just focused on the blazer-and-slacks crowd.)
When I want a low-price burger and a beer, I use our little club's reciprocal privileges and dine at the much larger and wealthier yacht club down the road!
They have a commercial kitchen and a bar.... we, OTOH, have zero paid employees, and no bar. We do, OTOH, have boat builders and mechanics.....