Devian --- dont listen to the fear-mongers
The A4 when properly set up, 'modernized' and maintained is probably more reliable, of equal weight (or MUCH less) than an oil burner. Rarely does a well maintained A4 ever wear out; the only 'usual' terminal problem is corrosion INSIDE the engine. Even if your engine is totally defunct, a precision rebuilt A4 will be 1/3 the cost of a new diesel; the diesel ALSO requiring new fuel tank/system, new beds, new propshaft/prop., new exhaust system, etc. etc. .... about $14000-15000. There are many proven aftermarket upgrades to this venerable and proven old A4 engine design: electronic ignition, fresh water cooling, etc. etc. etc. that will keep your A4 running for MANY years to come. BUT..... after you get this engine started do the following to assay if there is enough 'meat' (metal thickness) left to make any upgrades cost effective: simply remove one of the exhaust manifold bolts, carefully reach into the bolt bore/hole with a fine and bent probe similar to a dental pick .... and simply count how many threads you can 'feel' with that dental pick. If you can count 4 or more threads then you have enough 'meat' to accomplish the worst case --- rebuild. Less than 4 means that internal corrosion has exceeded the 'usual' and you should later consider to replace the engine (preferably with an A4 rebuild). A4s hardly ever ever 'wear out'; rather, their premature death is the result of internal corrosion (easily preventable with an aftermarket fresh water system upgrade) AND owner and 'mechanics' who have no idea of how to take care of one. HINT for future: never long term 'store' an A4 'dry' ... always keep the engine filled with 50:50 antifreeze -- to prevent/retard internal corrosion of the engine internals and exhaust manifold; never DRY. There is NO marine diesel engine of this size that runs as SMOOTH and reliable as an A4. Prepare to get a mortgage if you desire to change to a diesel. No small boat diesels are US made anymore, the $US has declined so badly in the past year and that due to todays 'currency exchange rates' the above $11000 estimate (2 years old) today may cost upwards of $15-16000 for a diesel 'replacement' .... then add the cost of the needed 'accessories'. Dont fall into this 'trap' and make the boo-birds richer. Do get a copy of Moyer's "Maintenance and Rebuild manual". Even if you are not handy with tools, etc. you can give/loan it to your 'mechanic' to use ... as there are damn FEW marine mechanics anymore who truly KNOW the ATomic 4. It was and still is a GOOD engine. Dont let the boo-birds and boatyard shysters tell you anything different. hope this helps. ;-)
The A4 when properly set up, 'modernized' and maintained is probably more reliable, of equal weight (or MUCH less) than an oil burner. Rarely does a well maintained A4 ever wear out; the only 'usual' terminal problem is corrosion INSIDE the engine. Even if your engine is totally defunct, a precision rebuilt A4 will be 1/3 the cost of a new diesel; the diesel ALSO requiring new fuel tank/system, new beds, new propshaft/prop., new exhaust system, etc. etc. .... about $14000-15000. There are many proven aftermarket upgrades to this venerable and proven old A4 engine design: electronic ignition, fresh water cooling, etc. etc. etc. that will keep your A4 running for MANY years to come. BUT..... after you get this engine started do the following to assay if there is enough 'meat' (metal thickness) left to make any upgrades cost effective: simply remove one of the exhaust manifold bolts, carefully reach into the bolt bore/hole with a fine and bent probe similar to a dental pick .... and simply count how many threads you can 'feel' with that dental pick. If you can count 4 or more threads then you have enough 'meat' to accomplish the worst case --- rebuild. Less than 4 means that internal corrosion has exceeded the 'usual' and you should later consider to replace the engine (preferably with an A4 rebuild). A4s hardly ever ever 'wear out'; rather, their premature death is the result of internal corrosion (easily preventable with an aftermarket fresh water system upgrade) AND owner and 'mechanics' who have no idea of how to take care of one. HINT for future: never long term 'store' an A4 'dry' ... always keep the engine filled with 50:50 antifreeze -- to prevent/retard internal corrosion of the engine internals and exhaust manifold; never DRY. There is NO marine diesel engine of this size that runs as SMOOTH and reliable as an A4. Prepare to get a mortgage if you desire to change to a diesel. No small boat diesels are US made anymore, the $US has declined so badly in the past year and that due to todays 'currency exchange rates' the above $11000 estimate (2 years old) today may cost upwards of $15-16000 for a diesel 'replacement' .... then add the cost of the needed 'accessories'. Dont fall into this 'trap' and make the boo-birds richer. Do get a copy of Moyer's "Maintenance and Rebuild manual". Even if you are not handy with tools, etc. you can give/loan it to your 'mechanic' to use ... as there are damn FEW marine mechanics anymore who truly KNOW the ATomic 4. It was and still is a GOOD engine. Dont let the boo-birds and boatyard shysters tell you anything different. hope this helps. ;-)