engine life expectancy

[searay30]

I been a proud owner of my 1989 30 sedan bridge since 2002. I never figure I,d own her long enough for her to become a classic but such is life. I bought the boat with about 300 hours on both mercruiser 5.7 straight inboards. Yesterday we rolled over 1080. We spent most of boating time in the nys canal system, the upper (Albany ny- Kingston ny ) Hudson river, a few days in the long island sound and the last 40 hours in Lake Erie.

The engines have been professionally maintained. No major problems except the replacement of the lower water pump in the star board engine. The boat has never been run hard under my ownership. ( I am the second owner ) She has many many hours at canal speed 2200 rpms or less and never much over 3500 rpms in open unrestricted water. The old girl runs along like an old shoe.

I think the days of long trips are behind us, but we still make our weekly trips to the beach and some week trips.

So my question for the group is what is the average or normal life expectancy of the engines? I have heard many different numbers. Should I consider over hauls? Some kind of inspection? or just keep pointy end of the boat headed towards the horizon.

Thanks in advance for any kind of insights.

 

[sbw1]

I owned a 1986 weekender with straight inboard 350s that I bought new and used for 10 years. Sold it and the new owner experienced a failure around 3200 hours. With normal good maintenance and keeping RPMS at 3250 or below, these engines last a long time. This is much better than average, but shows you what taking care of things will do for you. If they are running well, don't mess with them other than doing by the book maintenance.

 

[BillK2632]

You'll get lot's of opinions, but mine is a well maintained gasoline engine can easily run 2000-3000hrs - that's not totally free of repairs - you have to expect items like water pumps, alternators could potentially have problems. I don't consider those maintenance items, but wear items. The most hours I have had on one of my boats is 2000, the Correct Craft Ski Tique. The Commander Ford 302 was still running strong with no major repairs or problems. So at 1080hrs I would call your motors middle aged with plenty of life still left.

 

[Quint4]

Do a compression check next time you change the plugs to give you an idea where they are at.

I baby my 350s (825 hrs). I hope to get many more years out of them.

 

[SloBurn]

My 1988 7.4 L now has 820 hours on it. Does not burn any oil, no sign of any smoke, and runs like a top. I expect she is just about reaching her half life about now.

 

[searay30]

both my engines run great, don't burn oil, operate at the same temps. I have ben told these mercs don't get more than 1100 hours out of them before real issue begin to pop up.

 

[Gary Hill]

I have said it before and I will say it again. I have a friend at the end of our dock, he takes care of all his stuff. He has 5,500 hours + on his 8.1's. Still going strong.

 

[RollerCoastr]

I have ben told these mercs don't get more than 1100 hours out of them before real issue begin to pop up.

Naw - that's just docktalk. Aside from many, many of them going much longer than that, hours are a terrible way to predict an engine's life. It's actually all about maintenance and total fuel burned, which of course aren't as easy looking at an hour meter.

 

[Quint4]

Best tip I can give:
Do not neglect the exhaust. Be pessimistic about the exhaust components. Check them........they are the #1 engine killer. Big leak = sudden death. Small leak = slow death.

 

[searay30]

Very few hours in salt water, shows no signs of leakage. I asked my dealer up here on Lake erie to inspect them for leakage, he said he be happy to but manifolds on fresh water where the season is 6 months or less can go 30 years with being changed. but great advice.

 

[sbw1]

Very few hours in salt water, shows no signs of leakage. I asked my dealer up here on Lake erie to inspect them for leakage, he said he be happy to but manifolds on fresh water where the season is 6 months or less can go 30 years with being changed. but great advice.

We have boated on Lake Michigan for 45 years and have known lots of boats and their owners. Properly winterized engines and manifolds don't fail in this environment due to corrosion. They do freeze and crack. Nobody I know of checks them for leaks. Do your oil changes and pay attention to tranny fluid and antifreeze ph. Also, keep your RPMs reasonable.

 

[boatman37]

i bought my boat from the original owner who said the manifolds and risers on it have never been changed. there is about 600 hours on the engine. it was used on lake erie for its first 28 years

 

[Getaway]

Had 3100 hours on my 1988 454 big block before her first rebuild. Looking back, I did it as a precautionary measure, but the engine was running fine with plenty of power. She burned very little oil and did not leak oil at the time.

Upon rebuild, the guy who performed the job said he saw some cylinder scoring and the rings were in need of replacing. Other than that, everything looked good except the exhaust manifolds. Heads were redone and I replaced the exhaust manifolds, risers etc. I've got about 400 hours on her since the rebuild and she's a solid brute!!

I highly recommend not using conventional off the shelf oil and ethanol pump gas for any marine engine that has a carburetor. The older engines need a high zinc oil to properly lube the internal components. I use either Joe Gibbs HR1 oil or Brad Penn (the green stuff) racing oil. If I put a few gallons of pump gas in her, I'll run it right away or balance it out with more gallons of recreational fuel. I did have the ethanol fuel give me carb problems that were easily resolved.

The new off-the-shelf oils do not have the proper additives for the older marine engines.