How long should a mercruiser 140 (3.0L) last

[77trimate4]

I have a 77 trimate with a 3.0 140hp mercruiser, not sure how many hrs on it (no meter) I don't usually take it above 3500-4000 rpm, change oil once a year. Runs strong, dosen't use any oil. Just wondering what kind of life-expectancy this engine has.

thanks
Derek

 

[175checkmate]

29 years old and still going strong. Not to bad.

 

[77trimate4]

Should I be worried about it being 29 years old? it's spent its life in the midwest (nebraska) so I can't imagine it having really high hrs on it. I've read posts that I/O engines are only good for around 1000hrs, is there any truth to that?


Derek

 

[175checkmate]

It all depends on how they where used and the maintenance that was performed. A compression and leak down test will tell you the true condition of the engine.

 

[77trimate4]

my mechanic did a compression check, he said the numbers are what a new engine would have. He's one of those mechanics that dosen't trust anything mechanical, and can't find anything wrong with it. ...Should the engine in it's current condition, and the way I run it outlive the boat, or atleast the time I'll have it.

Derek

 

[vinny p.]

I would leave it alone. You obviously dont beat it up, so it most likely will be fine. We have cars at work with 10000 hours on the motors and they run fine.
If it were a performance engine, it would be another story. I'll be happy if I get 2 or 3 seasons on my engine before I pull it and rebiuld it.

 

[boatman4021]

In 35years of boating, the only 4cyl. Mercruiser(chevy) engines that I have seen with any major problems were from owner neglect such as not changing the oil(ever), draining the oil in the fall and forgetting about it in the spring(what an idiot). I have run the guts out of them my self and never had any mechanical problems. These are a great little engine. If it's not broke, don't fix it. Just feed it and maintain it. boatman

 

[Chris E]

until last spring my dad had a 1968 160 inline 6 - no major mechanincal problems in the time we had it - the new owner say its still going strong.

We replaced that boat with a sea ray with a 3.0 4 cyl - did compression on it and it came in within 2 psi of factory spec. The engine is a 1986 and runs fine. Like anything, run it gentle maintain it and you won't have any trouble. Keep the revs below 4000. Remember marine engines are just glorified truck and industrial (stationary) engines they were never designed for WOT all day long.

 

[Chris]

1,000 hours seems like a lot, but it's really not that much. For a car engine that's nothin'. I guess for a boat, it probably depends on how it was run. If it was babied it's probably still got lots of life. If it was run wide open the entire time...well, maybe not.

To give you some perspective though...I bought a new GMC Sierra last May. It has 21,000 K and the hour meter is already over 500 hours.

 

[daren34]

most boats only see 50 hours a year

sound like you 140 runs great

i would leave it alone

daren

 

[johnboyz85]

i had a 84,beretta made by mellhart with a 3.0 140 .It was my buddys dads boat and we skied &tubed many of highschool summers[class of 95] in it .So u know how we treatit.after grad,he sold it to his son,then after colledge abuse i bought it from him and ran it till 2000,then sold it to a guy here in town and i still see it at the lake.They have kids so they tube and ski .It still dont burn or leak oil,how, i dont know but that was one tuff little powerplant.lots of good memorys.