Engine Hours

[I_Just_Fish]

What is the average number of hours a outboard would have before you're looking at a worn out motor? Nothing technical, just plain and simple.

[bridgeman]

all depends on how it was maintained.

[I_Just_Fish]

Well just for the heck of it, lets say it is.

[GBS]

For small gas engines, I've heard the guestimate that at 500 hrs they need new rings.....and that sounds like a reasonable amount for an outboard as a wild guess.....at that rate, I will never have to buy a new motor (darn!)

[dutchboy]

It's just a question you can't answer. There are just to many variables to even hesitate a guess. How was it maintained? How old is it? What type of boat is it on? How many different drivers? What type of use did it have? Fishing, skiing, trolling,pleasure boating, racing..................the list goes on. If it's fairly new take it in and have the computer scanned, that will tell you more then we can.

[Gilligan]

For small gas engines, I've heard the guestimate that at 500 hrs they need new rings.....and that sounds like a reasonable amount for an outboard as a wild guess.....at that rate, I will never have to buy a new motor (darn!)

That number is way low. My 2 yr old Merc Pro Kicker has 800 to a 1000 hours already and running like a top.

A friend of mine has a 75hp Honda around a '97. That motor has close to if not 3000 hours if it has a minute. A number I heard before and to me is more realistic was 2500 hours.

[orchard frank]

My 15 HP 4 stroke Merc kicker has over 1500 hours and it still runs like new. Plugs look great when I change them, uses no oil, no smoke, etc. Oil changes, gear lube, plugs, and one valve adjustment is all it has required. I run QuikCleen or SeaFoam regularly. I also try to run it at high RPM's for a while after a long day of trolling. Big outboards may be somewhat different, although I know of some Mercs and Yamahas that have a lot (2000 +) hours on them, likely the same for any well maintained engine.

[Stroker]

I think the newer 4 strokes will have a much longer lifetime then the two strokes we are all used to. Having the crank case with a more suffisicated oiling system i think will pay dividents, although it does sacrafice on performance. Also they get to learn a lot of lessons from the automotive industry since a lot of the technology is simuliar.

I havent seen any Yamahas or Verados on the USCG boats but the Hondas that are on there i hear are getting over 6500 hours without any problems on there 225s. My buddy also has a yacht waste pump out company with a Honda BF115s he has had it since 1999 and has about 10000 on it and still nothing major. The Yamahas are good engines too and might be up there with them but just havent seen any with that number of hours.

[SteveJ]

For small gas engines, I've heard the guestimate that at 500 hrs they need new rings.....and that sounds like a reasonable amount for an outboard as a wild guess.....at that rate, I will never have to buy a new motor (darn!)

That may be true for small gas engines used in hot or dirty conditions, but I doubt it is even close for marine outboards. If you are using high quality lubrication of the appropriate specification there is no reason to expect to need to do a ring job. I would be far more concerned about some of the high tech components on our newer technology motors than rings.

My father is still running a 9.9hp Johnson that he purchased back in the 60's and it still runs like new. Can't say it doesn't burn any oil, as it is a 2-stroke motore, but it still starts easy and runs great.

[REW]

A few years ago, I was talking to a resorter in northern MN.
At that time we were talking about the life of 2 stroke outboard motors.

He stated that he would buy a motor - use it on his resort boat to run supplies to the resort from the shore stop. This meant that he genearally ran full throtte about 75% of the time.

He stated that at that time, he would buy a motor - change the lower unit oil, and spark plugs at recommended intervals and then swap out the motor when it hit 2500 hours.

He further stated that he seldom had a major motor failure in the 2500 hours that he typically ran the motor.

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If you equate this to typical northern water use, you might find that the average outboard actually runs about 100 hours per year.
This equates to about 25 years of useful life on an outboard.

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Lets say that we equate the 2500 hours to automobile use.
Lets further say that the average auto puts on its mileage at an average speed of 40 miles per hour.

Interestingly enough - 2500 x 40 = 100,000 miles.

For autos, these days, the average miles per year is 15,000 miles.
Or 100,000 / 15 = 6.6 years.

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I have talked to lots of boat owners and dealers over the years, and it is an interesting thing that is noted about boat ownership.
It seems that in the first year of ownership, many owners will put on 200-300 hours - even in these northern waters.

Then, the 2nd year is about 1/2 of that.
Then, the 3rd year is about 1/2 of the 2nd year.

Then, the following years seem to average out between 50-100 hours - depending on the particualr individual, family, etc. etc. etc.

You might say, that you put on many, many, many more hours on your outboard, because you do lots of fishing trips and spend a lot of time on the water.

However, before you are too hasty, think about the actual hours of use that an outboard is running on an average fishing trip.

Lets say that you go out fishing and leave the house at 5 am, and you return at 5 pm.
So, you say that you put 12 hours of use on your outboard.
Wrong ----
It takes you an hour to get to the lake, another hour to get home, so now we are down to 10 hours.
You take another hour to launch, load, and unpack, and pack the boat.
So, now we are down to 9 hours.
Now we are on average 20,000 acre lake where we take 15 minutes of crusing at 3/4 throttle to get to - and another 15 minutes to get back from the fishing grounds.

Now, we further find that we do a bit of spot to spot running during the day for another 30 minutes of engine running at 3/4 throttle.

The rest of the time is spent fishing - either anchored, drifting, or using the electric trolling motor, with perhaps another 10 minutes of running from the end of one spot back to its beginning.

So, we take this 12 hour day that we spent "fishing" and find that we have run our outboard motor for about 1 hour.

Now, we take the number of fishing trips and multiply by 1. Lets be generous and say that you fish 50 times during the year.
That means that you have put on a total of 50 hours on your outboard motor.

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Now, take another example.
Lets say that you have a fish and ski boat, and you use it for both fishing, cruising, as well as family activities. Lets also say that you have 3 teen agers who love to water ski.
Now, we take the boat out for a family day, water skiing and tubing.
We hit the water at 10 am in the morning, and ski and tube until 6 pm in the afternoon. We further find that about 80% of the time is spent at 1/2 to full throttle for a total of 8 hours - in one weekend.
Lets further say, that the boat is used 2 weekends a month for the entire summer, as well as a week at a resort with the family. Now, we suddenly have 48 hours of use for the weekend, as well as another 100 hours of use for the week at the cabin. Now, we also add in the 50 hours for fishing, and another 20 hours in for cruising.
Now, we are looking at 170 hours of mixed, fishing, cruising, skiing and tubing.

Obviously, none of these numbers are exact, but can be somewhat representative of different boat users and their use.

Take care
REW

[bridgeman]

If your unsure you can always have a compression test done by a reputable mechanic..you want a compression leak down test done and I would avoid any engine that reveals a >10% loss providing that the engine has only minimal carbon build up on the rings.

[slow troll]

I too think 500 hrs. is quite low. It might apply to a BS powered lawn mower from Wally World, but OBs are water cooled and built much better. There isn't a lot to fail in a carbureted 2-stroke engine, but most will succumb to poor maintenance, forgetting to mix, hitting obstacles, submersion or other stupid boater tricks long before wearing out.

Diesels are generally regarded as candidates for overhaul at around the Billion rev mark...with good maintenance. That's a billion revolutions regardless of power setting. They run at much lower RPM than an OB but are subjected to much higher compression stresses.

A billion revs on an OB at 5000 RPM, comes up in 200,000 minutes or 3,333 hours....4167 hours at 4000 RPM. This seems to correspond well with the reports from experienced operators quoted above. I wouldn't be surprised to learn that the billion rev lifetime between overhauls is a design criteria for outboard powerheads as well as diesels.

Gives one a greater appreciation for how big a billion is...and for the billions of taxpayer $ being blown by the government to cover for the subprime disaster.
Bob

[Stoker]

Unfortunately they dont really make outboards like that used to. The carburated 2 stroke is on its way out and being replaced by the direct injected motors which have all those computers and elctronics on them that take away from the simplicity. Even them inplimentation of the oil injection especially those VRO systems have caused problems with the 2 strokes. Now if someone can find out how to make a carburated 2 stroke clean then we would really be on to something...

[San Chan]

A few years ago, I was talking to a resorter in northern MN.
At that time we were talking about the life of 2 stroke outboard motors.

He stated that he would buy a motor - use it on his resort boat to run supplies to the resort from the shore stop. This meant that he genearally ran full throtte about 75% of the time.

He stated that at that time, he would buy a motor - change the lower unit oil, and spark plugs at recommended intervals and then swap out the motor when it hit 2500 hours.

He further stated that he seldom had a major motor failure in the 2500 hours that he typically ran the motor.

--------------
If you equate this to typical northern water use, you might find that the average outboard actually runs about 100 hours per year.
This equates to about 25 years of useful life on an outboard.

REW



I generally put one hour average on the outboard every trip out fishing (Trip Calculater on GPS Stated that), and 80-100 days fishing. IF my 90HP 4Stroke can do 2500 hours, that will be more than 25 years. Wow, money well spent........

[ENGINEDUDE]

As a general rule with great maintenance a Two stroke will go 2000 hours, Four strokes 10000 hours.

[bob oh]

Enginedude, could you cite a study or authority for you hours statement?

[bridgeman]

Take note the next time you watch someting on discovery channel or national geo. look at the old evinrudes yammies and merc's on the back of those old fishing tubs that fish squid. There all 2 strokers that I'm sure have more than 2k hrs. Its all in how you take care of them, stuff still fails for no reason but if you don't beat the crap out of it you'll get the service out of it.

[GBS]

You guys are making me feel worse and worse. With the price of gas falling, I'm going to have to start aiming for rocks and stumps to convince the wife I need to repower my boat.