Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
The A4 engine is a very uncomplicated, reliable gas engine. The last I heard (about 2 years ago), parts were readily available to repair everything except the engine block itself. I know of one that was about 1959 or 60 vintage that the owner told me finally gave out because the water jacket rusted through. My friend and I made countless 30 mile trips with his during a 15 year period, and it was very trouble-free, right up until it finally died. I'd say 58 years is good longevity for a marine engine. Most outboards can't compare.
For a small boat, an outboard engine usually makes more sense. If any inboard engine needs to be removed to repair it, the labor cost is prohibitive. You can remove an outboard engine yourself and carry it to the repair shop. If you get one that's sound and can perform routine maintenance and minor repairs yourself, it would probably be a good choice, as serviceable as a diesel, and the purchase price for a boat with an A4 should be less than a diesel.
Steve Milby J/24 "Captiva Wind" previously C&C 35, Cal 25, C25 TR/FK, C22 Past Commodore
I would look at whether the cooling system is raw water or fresh (with a heat exchanger). If raw, has it been used in salt water during its life? If so, I'd walk. The block is cast iron, old, and corrosion in cooling passages is likely and will be fatal.
Dave Bristle Association "Port Captain" for Mystic/Stonington CT PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired), Now on Eastern 27 $+!nkp*+ Sarge
A4s were produced until about 1984, so, depending on its age, it could still have a useful life of 20-25 years. If it dies, you could easily replace it with an outboard motor, depending on the size and type of boat. If the boat is a C27, for example, mounting an outboard would be easy. Whether the particular A4 is a good choice depends on the particulars, but in general, the A4 is a very good old gas engine.
Steve Milby J/24 "Captiva Wind" previously C&C 35, Cal 25, C25 TR/FK, C22 Past Commodore
Moyer Marine is the single keeper of the facts; upgrade champs; go to source for EVERYTHING Atomic 4. They are, as stated, simple, easy to maintain, engines.
Peter Bigelow C-25 TR/FK #2092 Limerick Rowayton, Ct Port Captain: Rowayton/Norwalk/Darien CT
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.