Very happy with a Volvo TAMD41P-A (SIX cylinders, not four - standard engine for many years except earliest years), hull number 232, April 2005. Later in the 2005 model year Camano switched to the Yanmar, but I don't know at which hull number. Haven't needed any parts in 7 years of ownership, aside from filters, routine scheduled replacement of inverter, hoses, etc. Can't speak to the Yanmar, but I haven't heard any negatives on various forums. My RPMs are a few hundred less than what a Yanmar owner noted speeds posted in a 8/4/24 post above. Synthetic oil like Rotella T-6 15W40 cut my operating temp about 5 degrees, noticeably reduced old sludge - oil is progressively cleaner at the end of last few seasons since going to T-6 - using almost exclusively Valve-Tech fuel - runs smoother, quieter.
Both yards I've used talked about engine being "sweet". When purchased the exhaust had accumulated thick, wet carbon, mechanic had to dig it out. Following a Steve Zimmerman article in PassageMaker talking about running at a higher "percentage of effort" being key keeping exhaust, etc., clean, I've slightly upped my normal cruise speed. 7 years later exhaust is far cleaner, very light wet carbon when exhaust was checked this summer for the first time since 2017.
I hope you'll post what you find out about the Yanmar, and let us know which one you choose. Camano is outstanding for our uses - RI to NC delivery cruise, and traveling to eastern NC lovely colonial towns. Sleeps great, flybridge is delightful, lots of compliments on traditional west coast working boat look, which will never grow old.