www.iFourWinns.com

How many hours on a V8 motor before I should consider a rebuild?

You should consider it if the compression is less than limits required by Mercruiser/Volvo, OMC or the oil pressure is so low (due to excessive bearing clearance).

Most marine engines don't wear out. They usually fail due to owner neglect ..........cracked blocks, overheat, loss of oil pressure(due to not checking/changing it)

My previous boat with a 1966 Mercruiser inside went 39 years and still ran ok with over 2000 hrs on it....


Cheers,


Rick

_________________
1987 Four Winns Liberator 211, formerly OMC 460 King Kobra powered, replaced in 2006 by a 1997 Mercruiser 454/Bravo III

Thanks! So assuming good compression and oil pressure, 400-500hrs shouldn't be in need of a rebuild or replacement? That's good to hear, a couple boats I'm looking at have 450 or so hours and I was concerned about engine life.

Someone once told me that 1000 hours on a boat is the equivalent to 35,000 miles on a car. Don't know how true that is, but it makes me feel better since my 5.0 Volvos have 880 hours on them (each).

_________________

Current Boat: 2000 Four Winns 298 Vista
Previous Boat: 2000 Carver 406MY

Well, to start ....

Our 2001 Suburban actually tracks engine hous as well as vehicle mileage (you can display the hours via the mileage & trip display). It has about 4000 hours on it.

Ok, that's great, so an 800 hour boat engine (gas, of course) is at only 1/5 the wear/life of my 'Burby. Cool, right?

Well, not exactly.

The average RPM, for all those hours, on the 'Burby is probably around 2000-RPM (if that ...). The average RPM on the boat is more like 3000-RPM (or more, depending on the application & use). Additionally, the typical torque load on the 'Burby, during regular use, is far less than on the boat engine (I don't typically accellerate as hard, in the 'Burby, as in the boat ... just to get it up and going .... and even the cruise torque is much higher than in a vehicle that's just cruising along).

Soooooo ............ while the maintenace of the engine will have A LOT to do with the life cycle of the marine engine, it will typically not last as long as a properly cared for street vehicle engine before it is in need of a freshening.

_________________
Gordon Arnold
New Hampshire

2003 268 Vista ..................................................................Prior: 97 245 Sundowner

You have to go more by actual condition than hrs on the motor....compression test...operational test...oil pressure and temp readings...if the engine has good comression...good oil pressure...doesn't run hot and runs smooth...no oil burning smoke...I wouldn't worry...freshwater use...as long as it's maintained...oil changed each season...winterized properly...and was properly propped (so the engine could reach its max rpm and not labor) 2000 hrs is not unreasonable...
However...if the oil was not changed each season....or it was run overheated...or someone had a prop with too much pitch so the engine labored to get the boat on plane...then all bets are off...

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Curious. How many miles does your Suburban have on it given the 4000 hours? Thanks.

_________________

Current Boat: 2000 Four Winns 298 Vista
Previous Boat: 2000 Carver 406MY

Had 900 hours on my ski-boat when I sold it ( TIGE ) 351 Indmar engine. 90% of those hours were hard run hours. At about 800 hours I had to replace the starter locater plate. While the engine was out the oil pan and valve covers were removed just for a look / see. Granted you really can't see much that way but that was the time to do it. It looked like a brand new machine. Since oil changes were so easy as the boat was trailered it got changed every 50 hours. A little excessive maybe?

Also put an Eldebrock high rise aluminum manifold on it, the top end looked new also.

If you have all the maintenance records for your boat this may give you a good idea of the care the engine had.

9BALL

PS: most of the time the engine was run between 3600 - 4100 RPM depending on what we were doing.

_________________
2005 V268

I'll try to remember to double check the actual hours (been quite some time since I have looked, I'm sort of guessing at the 4000 example) and the mileage. Mileage is about 140K. The engine is the Gen-III 6.0 (LS family).

_________________
Gordon Arnold
New Hampshire

2003 268 Vista ..................................................................Prior: 97 245 Sundowner

Not too bad.......My 94 (6.5L diesel) Suburban (bought it new btw) just turned over 180,000. I just finished a trip to Ca and back last weekend and after driving about 1700 miles pulling my (5000lb) 211 Liberator, only used about 1/2 qt of 5W-40 Shell Rotella T synthetic oil!

I also got 14.0 mpg from Tacoma to Southern Ore and Between 12-13 for the rest of the trip pulling that thing from 60-70 MPH.


If I had driven that thing at a constant 60 mph, that would calculate out to 3000 hrs. Considering that I don't always drive all freeway etc....the actual hours is MUCH (at least 50% ) more.

The hr meter on my 1966 MarkTwain(150 Mercruiser) broke at 1500hrs in the late 70's to early 80's while my dad still had it.....I didn't get it until 1997 and he used it pretty much every summer and at other times up to that point....I'm guessing it had conservatively, at least 3000hrs on the engine when I sold it....it was getting tired but it still ran pretty good...





Cheers,

Rick

_________________
1987 Four Winns Liberator 211, formerly OMC 460 King Kobra powered, replaced in 2006 by a 1997 Mercruiser 454/Bravo III

150,750 miles

4634 hours

I wish it was diesel .... we get about 10 to 11-mpg non-towing (maybe can stretch it to 12 in highway only). Towing (the boat) is probably 8 or 9 mpg.

_________________
Gordon Arnold
New Hampshire

2003 268 Vista ..................................................................Prior: 97 245 Sundowner

Speaking of this, I checked while I was in my wife's Grand Prix. 1,946 hours, 73k miles.

And I hear you on that MPG...my Durango gets 12-13 regulary, and 8-9 towing the boat. I do have a bit of a lead foot though.

_________________
2007 358 T-5.7GXi IB
Previous Boats
'08 H240, '08 V318, '04 268, '04 225

Thanks for looking that up. So the old saying that "a thousand hours on a boat is the equivalent to 35,000 miles on a car" is correct. However, I do agree with most that use (RPM's) and maintenance dictate the life of an engine.

_________________

Current Boat: 2000 Four Winns 298 Vista
Previous Boat: 2000 Carver 406MY