Diesel Engine

The Catalina 34 has had at least three different motors. The M25, a 21hp engine, was installed on the the early models. The M25XP (23 hp) became standard in 1988. The M30, a 4 cylinder producing 28hp, became an optional engine about the same time and is standard in the Mark II. All are produced under the Universal Motors brand (now Westerbeke Corporation). Due to lack of available supplies, the factory occasionally installed a Yanmar engine (note: Yanmars are higher-compression engines, which do not require glow plugs).

Cooling

• Exhaust pipe replacement
  
• Heat exchanger maintenance, including zinc change
  
• Heat exchanger upgrade to 3" version to prevent overheating
  
• Hump hose replacement guidance
  
• Overheating as a result of an air lock
  
• Raw water pump and cooling system (Just a little info here; so, please add your own more comprehensive overview and maintenance article here)
• Raw water pump: Loss of self-priming capability
  
• Water heater doesn't heat when motoring
  
• Water-lift muffler: Repair or replace?
  
• 3" heat exchanger mounts
• Water Pump Impellers

Electrical

• Alternator mount/bracket upgrade Important safety upgrade for M25 (not XP) owners
  
• Engine harness upgrade: A comprehensive overview by Gerry Douglas Important WARNING for M25 owners
  
• Engine harness upgrade by Capt. Al
  Important FIRE HAZARD for M25 series owners
  
• Glow plug solenoid Installation for faster starting
  
• Secondary start switch
  
• Slow start fix with a wiring upgrade, starter re-build, and new starting battery by Mike Vaccaro
  
• Tachometer Malfunction Q&A
  
  

Fuel

• Fuel issues and advice (takes you to another section)
  

Mechanical

• Adjusting Valves (Be the first to contribute your experience here!)
  
• All about alternator belt tension & pulleys
  
• Air Filters (Be the first to contribute your experience here!)
  
• Blow by (Be the first to contribute your experience here!)
  
• Changing engine mounts
  
• Engine mount protector
  
• Oil change hose replacement project
  
• Oil pan replacement project to fix leaking oil Pan
  
• Rebuilding a M25xp by Dave Sanner
  
• Replacement filters, belts, and oils equivalents list: find alternate replacement brands
  
• Solving engine power loss: Working on the injection pump
  
• Transmissions: Checking the oil
  
• Transmissions: The right gear while under sail
  
• Transmissions:Hurth Transmission Cable Adjustment PDF file
• Universal Diesel Model 15 and 25 Service Manual

Misc Projects

• Engine compartment cover hinge
  
• Removing Engine Using Boom

Shaft & Propeller

• Flexible coupling installation
  
• Propeller" (Be the first to contribute your experience here)
  
• Shaft Alignment
  
• Stuffing box (takes you to a separate section on the stuffing box)
  

Also of Interest

• Diesel Info at Wikipedia
  
• Engine Manuals
  
• Parts Catalog