life of engine

[hudman]

I am looking at a mercruiser 350 mag motor, complete, 2002 model, with 600 hours on it.<br />although the mechanic selling it states that it runs great,,, he told me that the owner of the boat was upgrading because he was having trouble plaining off with several people on his boat, and wanted more power,, this tells me that the power was starting to fall off on this motor...What is the life of one if these before a rebuild? thanks for your help, love this site, read it daily

 

[MrBill]

Re: life of engine

Good question...and I'd like to hear some of the responses because I just read in Boating Magazine (February 2006 edition) that...in general gasoline powered boat engines run 500 hours before overhaul may be required, and diesels can be expected to run twice that...a 1000 hours. I find this to be way on the low end. Avid boaters here put 50 to 80 hours on their boats in a season (short New England season). I have well over 1000 hours on my Mercruiser gas engine and outdrive without any major rebuild or rework, and I expect a lot more without problems.

 

[Bondo]

Re: life of engine

In My Experince,.........<br /><br />1500/2000hrs is Not Uncommon for a Properly Maintained motor........<br /><br />An Engine Survey would be Your Best Bet........<br /><br />Compression,+ Leak-down tests will Tell you Alot..........

 

[Don S]

Re: life of engine

Depends on too many different variables.<br />An engine overpropped will have an overloaded engine ALL the time and won't last long.<br />An engine run at WOT all the time won't last long.<br />Then there are the maintenance issues. No maintenance, no long life.<br /><br />

he told me that the owner of the boat was upgrading because he was having trouble plaining off with several people on his boat,

This could also mean the original owner bought an underpowered boat. Manufacturers love to sell the underpowered boats at boat shows with low prices.

 

[hudman]

Re: life of engine

True, Don, but the way the mechanic described it, something had changed in the boat to cause this problem....I personally put at least 5 hours a week on my boat, sometimes 10. I live and work 5 minutes from my boat, and go out on the river a lot at nite, in summer,,, kind of a "INSTANT GRATIFICATION" for me after a long day at the office. the owner of this motor had no trouble when it was new, probably in 2002,,,

 

[Doug Durako]

Re: life of engine

That is just a bit more than average hours for a pleasure boater--what did it come out of?<br /><br />If it was taken care of (and I would get all mainetenance records and history on it) that motor should be rarin' to go, if you put it in something under 24 feet with the right drive and prop.

 

[hudman]

Re: life of engine

dont know what it came out of, but if i get it its going in a single engine cruiser<br />mine is a bravo 2 and it came out of a bravo 1 so it should work. my main concern is maybe wear on engine.. it has all maintence records with it.

 

[rodbolt]

Re: life of engine

beats me, I have a few with over 9000 hours that are still happy and burn no oil. mostly it depends on how it was set up and if you maintain it, by maint I dont mean an oil change once a year. the oil is the least of my maint worries.<br />in my area the two biggest killers are salt water corrosion and what it does to cast iron and seawater pump failures.<br /> when my cousin asked me about setting up his 330 MIE in a 30 ft custom crab boat I spent a few of his nickles that everyone laughed at. he has about 12000 hours on it and it just goes.<br /> every 6 months we rebuild the seawater pump and every 3rd rebuild it gets a new pump. we have a 10 micron fuel water seperator in front of the fuel pump that gets changed every 30 days.<br />we installed a reverso oil changing system to ease the oil change issues. block and manifolds are freshwater cooled with a larger than stock heat exchanger, risers are cast stainless that in 94 were about 600 each and every 3 years we pull them and clean the scale.<br /> clutch is a velvet drive 72 series 1.98-1 and we pull it every 3 years to change the input shaft seal and lube the splines, starter is top mount rear entry to ease that issue as well .<br /> oil pan is a 10 QT aluminium. no rust hole issues.<br /> my uncle has a 33 shad boat buil;t about 1915 that has a marine power 7.4 that I installed in dec of 95 that he crabs with. we estimate it at about 8000 hours. almost the same set up but he did not opt for the stainless risers and just changes his every 3 years or so. but as he lets me tie up at his dock year round I asssit with the care and maint. biggest issue so far is the pickup coil on the EST ign. seems to corrode one out about every 3 years.<br /><br /> now we will shift to the underpowered, run it till something breaks maint schedule, saltwater cooled motor. if it goes 6 years and 250 hours its done.<br /> choice is always the customers.

 

[f_inscreenname]

Re: life of engine

Before any "used" motor would go in my boat it would get a rebuild. Some new ring and bearings in it and you will have a new motor good for another 6000 hours. You get all the power of a new motor also. To much work pulling and installing a motor not to rebuild. There is no worse feeling to get everything buttoned up just to fine out the motor is a POS and you have to pull it again.

 

[rodbolt]

Re: life of engine

what F says.<br /> open it up and at least have a look.<br /> it boils down to economics.<br /> most customers eyes glaze over once they get past the fancy plastic interiors.<br /> thats all they see.<br /> its tough to sell them 3000 dollars worth of options even though over the course of 10 years or so it will save money and aggrevation.<br /> I think the composite oil pan is about 250 dollars and the cast Al one is close to 400. the stamped steel one (replacement) is about 300 and requires engine removal to replace. I replace 5 or 6 every year due to holes rusting in them. <br /> I cringe every time I go to the boat show and see the latest whiz bang platic boat with touchpad controls and a million watt 10 speaker surround sound set up that will require hull dissasemply for maint yet it has a saltwater cooled engine with a stamped steel pan and the bilge pump is so inaccesible your not really sure it has one. couple that with plastic through hull fittings,especially below the water line, and the flat pack wire connectors that are not even moisture resitant and your begging for greif in 3 years.<br /> but its cheap and they sell a lot of them, 3 years into it I get my money.

 

[hudman]

Re: life of engine

Thanks Rod,,,, this boat/engine will be used in freshwater only. the hull is a 97 and we have no problems with anything else, just want a newer fresher engine..... i think ill try to get this one, and maybe have bearings/rings replaced before installing it.. ive got another month here until boating season starts again....

 

[Cptkid570]

Re: life of engine

If it's a mechanic selling it, then the mechanic shouldn't have a problem doing a compression test for you. If compression is good, then you can feel more comfortable with your investment.<br /><br />Just out of curiosity, what is he selling it for?

 

[hudman]

Re: life of engine

it ended up selling for about $2400. it as a 2002 mercruiser 350mpi mag motor, complete, fuel injected,,,drop in. sold by a mercruiser dealer 20 miles north of detroit,,,, ended tuesday on e bay... snipe bidder got it in the last 3 seconds.

 

[Always Broke]

Re: life of engine

Try not to let it bother you Hudman. When you buy a motor you cannot hear run or at least be there to do a compression check to let you know what shape the valves, rings, head gasket, block wear, etc…. are in, your buying as my dad would say “A pig in a poke”. If you got to see the maintenance records he had it would have give you a good clue to the shape of the motor too. If you see something like changed water circulating pump, thermostat, hoses, raw water pump, pretty close together it tells you the motor was probably overheated, not a for sure thing but if it walks like a duck and quacks like a duck…it’s not a good thing to happen to a motor, it dose not mean there was other damage done but there’s a better likelihood of it no matter how many hours are on the motor. If I were buying a motor sight unseen without a warranty I would want it for parts price incase it ends up costing more then what it’s worth to fix it you have a chance of getting your money back. As far as the life of an engine goes, just think of the cars that you drive, I’ve gone well over 100k in some without a hitch and didn’t make it past 30k in a few without major problems and I treated them all the same, everything mechanical breaks, even if it’s well taken care of it’s just the luck of the draw at times. Just one old mechanics opinion.