I sent an email to
info@irwinyachts.com and it bounced back. If you can’t find an owner’s manual for your boat, suggest assembling your own. Start with a table documenting the boat's specs, engine/transmission, tankage, construction details, electronics, electrical, pumps, docking quipment, safety equipment, galley and head equipment, accessories, upgrades, etc. with manufacturer and model and download the manual for each from the manufacturer’s website. Also make diagrams for plumbing and electrical systems in Visio or Excel. That is what I did for my 2005 Hunter 46 and 1984 Symbol Sundeck (no manual) to augument the manufacturer's "general" manual or lack there of.
Below is a starting point for information on the Irwin 34 Citation Send me a PM and I would be happy to send you an example of what I did for my Hunter 46, which I had a manual, and a 1984 powerboat, which did not come with a manual.
SailboatData.com - IRWIN 34 CITATION Sailboat
Citation 34 Used Boat Review (spinsheet.com)
Irwin Citation 34 - Practical Sailor (practical-sailor.com)