How many hours will a marine engine run?

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
What rpms did the diesel run at? They usually run a lot slower than gas engines.
Those USCG outboards must have really been driven hard. Even back in the 1960s, the big 3 were expecting/designing >1000 hours at WOT.
 

Peter Eikenberry

Chief Petty Officer
Joined
Sep 3, 2007
Messages
408
The Coast Guard is famous for abusing their boats and of course taking good care of them, If they don't work properly it puts you the public at serious risk. But yes, lots of WOT in heavy weather, towing boats that are far larger than the CG boat, and the boats in question often went into really shallow areas in the San Francisco delta and sucked up a lot of sand and mud (not to mention all the other crap in the water) In other words, really heavy duty use. Not anything like the average boat owner. The boats I am talking about were 22 foot aluminum SeaArk work boats with twin Evinrudes. . Besides the usual SAR, law enforcement and patrol work they were also used a lot for escort duty for visiting dignitaries (Queen Elizabeth was one) and escorting oil tankers and Naval vessels. Typical USCG work.
 

airshot

Rear Admiral
Joined
Jul 22, 2008
Messages
4,222
I do not have an hour meter on my boat, but do know of the boats history so...I have a 1983 3.o 140hp mercruiser I/O. The boat was originally used in lake Michigan trolling for salmon and other fish species. The boat was bought by its second owner 8 yrs ago, second owner redid the interior but the motor ran fine. I bought the boat from the second owner almost 6 yrs ago (his wife wanted a bigger boat) Just last year I redid the head as compression was low between 2-3. WQhen I removed the head the cylinders were excellent, resurfaced the head, ground valves, and new head gasket. Block deck was flat as a pancake, so.....how many hours does a 1983 boat have on it? Was used every year first in lake Michigan and it last 8-9 years in Lake Erie and it still runs and start like new but has had normal maintaince according to the manual. Boat is 34 yrs old, at an avg of 50 hrs per yr that comes to 1700 hrs and I know my avg has been around 60 hrs per year while I have owned it. Just an example of what can be gotten from a marine engine.
 

Grub54891

Vice Admiral
Joined
Jun 17, 2012
Messages
5,908
I have a mercruiser 120, and a 140, 1983, and 1985. Both run excellent, changed them over to electronic ign when I got them. No idea on the hours on either, both had several owners before I got them. The 140 had the core plugs blown out, but nothing was wrong otherwise. I should check compression, but I don't see the need, they do not use a drop of oil, and now as the owner they get regular maintenance. A motor will last a long time if it's taken care of.
 

rick3452

Petty Officer 1st Class
Joined
Oct 26, 2010
Messages
282
My 2000 5.0 Bravo 3 just hit 2100 hrs, I use it daily and seldom run it over 1200 RPM's because I use it exclusively on the intercostal in Fort Lauderdale. (speed controlled) ,I usually get to open it up once or twice a week for short runs. I change all fluids at 100 hrs without fail which in my case is 3/4 times a year.. Constant maintenance is the key...
 
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