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When to replace or rebuild engine

chollyjohn

Regular Contributor
"In my most recent quest to pu

"In my most recent quest to purchase a boat I have encountered a troubling quesiton. The boats that I am looking at are 1989-1993 years. I feel construction was good then and I would have a trusted hull (surveyed of course). I am seeing boats with the original engines on them. 17 or so years old and ranging from 350 - 1150 hours of operation based on the installed hour meters.
I have consulted with several mechanics and the synopsis is this. Regarding raw water cooled engines; a life span can be expected of approx. 750-800 hours; for fresh water cooled a range of approx. 1150 - 1500 hours.]
But in the case of my boat search and eventual purchase, those boats having less than 750 hours raw water cooled are also 17+ years old. I feel I need to budget in dollars to repower the boat. The controversy is that boat brokers praise the low hours on a boat in their inventory and which also restricts any negotiations with the owner to discount the boat due to the age of the engine and not necessarily the hours on the engine. I appreciate anyones comments concerning what is the standard (if any) about needing a repower or rebuild due to age."
 
"Charles, all your questions a

"Charles, all your questions about hours and life expectantcy depends on the type of engine you are talking about. Engines and applications have different life expectanty. I would need to know the engine type, let me know.

Regards,
Greg"
 
"The boat I am looking at has

"The boat I am looking at has the original engine and outdrive. The boat is a 1990 Sea Ray 270DA. Engine is 1989-90 Mercruiser (GM) 454 (7.4L) long block, RWC, carburated, rated 300 hp at engine; 330 HP at outdrive. The outdrive is Bravo II; 2.00:1 ratio. I have been told by the broker that the engine was cared for by certified marine service over the years; the engine was winterized; it is operational yet has been in the yard for two seasons not used.
Pictures look great however, I cant see it first hand since the boat is in NJ and I reside in Virginia. Hope this information helps. If I choose to purchase they commit to a sea trial and I would basically havethe compression tested and the outdrive pressure tested. Other than that I think only a visual of the overall condition could be determined."
 
"Charles,
I think there ar


"Charles,
I think there are a few other tell-tale signs that I look for.Like how many bolt heads are missing paint.Oil marks where they could not clean very easy.Is there no receipts to repairs or winterizing on this boat?What does the oil look like and if you are paying for a compression test, why not get the oil analyzed as well.To be honest with you I would plan for expenses as you are dealing with a 18 year old boat.Anymore the drives cost almost as much as the engine.Hows the coupler,bellows,shift cable.Bottom line to me is are you happy with the way the owners before you kept the rest of the boat,and yes I would set some money aside, not including how much you will most likely spend personalizing it to your liking...Todd"
 
"Todd:
Appreciate your commen


"Todd:
Appreciate your comments and added tasks to check out the engine and outdrive. I contacted Sea Ray and they gave me some pointers too as well as Mercruiser. The feelings are same that the engine due to age has expended it's life. Even teh best care over 17 yrs with RWC leaves the engine with a good deal of corrosion. I can spend it on repower, or spend my money year after year re3placing things not to menton down-time to enjoy the boat. Like an old car sitting in the garage for years, once you start really using it, it starts to fall apart. Face it, its hard to get a jump start on the water 5-10 miles off shore. I'll plan on a repower within the next year. Thankx again."
 
"I agree with you Charles...Mo

"I agree with you Charles...Most people buying a boat with age never plan that way and are in for a big let down when it happens.New boats have parts that break,so with older ones its usually one thing after another, but you can get ahead of it with time and effort and a few pennies...Todd"
 
"Time alone is not the enemy.

"Time alone is not the enemy. Salt, cold, corrosion, abuse and poor maintenance are. My raw water cooled engines are 27 years old and run great, but I am in fresh water. 1200 hours and no signs of trouble. If the Sea Ray has been run in salt water (New Jersey) and not properly flushed after use, the salt will have started to eat away at the water passages, pump vanes, manifolds, elbows/risers and any other metal parts it touches. The history of the boat can tell you a lot about its future."
 
"Thankx Peter. I have already

"Thankx Peter. I have already decided, that it would be wise to have the engine partially dismantled as needed to assure proper cooling and replace such items, if needed, like pump housings, risers and other major parts if it is noticable that much corrosion exists. The option however, is that replacement (new) engines can be aquired at resonable prices in today's market with same or increased HP and torque ratings. Mercruiser has been helpful in sharing some of their criteria of the boat design and how they rated the boat in 90-93 with the 325HP and Bravo II drive with proper ratios. Also they have helped in determining proper (initial) prop size. I may have to modify however based on my average load and eventually adding a genset in the engine compartment. Im told engines run in fresh water are great provided you keep them in fresh water. After approx 100-150 hours, even a fresh water engine has lost it's protective water pasageways and in such event you then put it into a salt water condiiton, many owners find themselves quickly replacing the parts you mention not to exclude problems that start with gaskets, the head and drive seals. I took Mercury's advise. I never had a inboard engine in fresh then salt but I had the experience with two previous lake boats with outboards and once they were exposed to salt conditions, problems quickly started, and I am not one to fall short on any maintenance or flushing of the cooling systems. Your comments, and that of Todds along with Mercury and Sea Ray have proven time well spent. It's an educatuon...well I'd rather call it an adventure. No test required."
 
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