Outboard Motor Longevity Guide: How Long Do They Last?

Whether you have an old boat and old motor or you have a new motor, it is important to know how much your outboard motor will give before it gives out. There are many things that can affect the longevity of your outboard motor from maintenance, to age to model. Let’s break down what each does to the longevity of a motor so you can know how long yours has, or which motor you want for future reference.

On average, an outboard motor will run about 1,500 hours or 7 to 8 years. Each outboard motor will be different but if you keep up maintenance and take care of the motor it can last much longer.

Depending on our needs as anglers, different outboards will be better for us. Whatever outboard we decide fits our needs best, if we take care of our outboard motors, they will take care of us and our boating needs for a good long time.

How Long They Last

So, let’s dive into how long these outboards will last. On the website Boat Safe, the following is said about this.

“The number of hours that a marine engine runs is very dependent on the amount and quality of maintenance over the years.”

Boat Safe

Later we’ll discuss how one can maintain an outboard motor to make it last longer. But, maintenance isn’t the only thing that can keep an outboard running. If an outboard is used every day is it a lot more likely to last longer. On the forum website, The Hull Truth one senior member of the forum replies with the following to the post, “Life Expectancy of Outboard Motors”.

“It all depends on how its used and cared for. A well used and well maintained engine will last longer than an engine that sits and doesn’t get used or maintained. This is why the commerical guys get so many hours out of them. A 5 year old engine with 400-500 hours on it will probably be more reliable than a 5 year old engine with 20 hours.”


When outboards are taken care of, many people claim that these outboards can last for as long as you need them to. Again on The Hull Truth, a senior member states the following about outboard longevity.

“You will have electrical issues and starter rebuilds maybe even replace a trim pump but there is no reason that these motors shouldn’t last several thousand hours.”


On The Hull Truth, another senior member said the following.

“They will usually outlast the hull if maintained & run properly.”


What Causes Outboard Failure

Outboards are known to have problems and have things break rather than them simply wearing out. That’s why outboards last so much longer if they are taken care of and maintained. When outboards are left to sit without much use, or if they are used without being check up on, they often tend to have several problems. On a forum on Marine Engine‘s website, one boater replies with the following.

“The one thing that is responsible for many outboard engine failures is lack of use. When engines are allowed to set up unused for long periods without proper preparation, a surprising number of things can go wrong.”


So, what are those things that can go wrong? The website Florida Yacht Management has a great article about what some of the main culprits of outboard problems are and how they can be solved.

Electrical Problem

If there is a problem with the outboard, an electrical problem is a common suspect. Check the battery and connections to be sure everything is connected and free of corrosion.

ProblemPossible Cause
Outboard won’t start. Dead battery.
Won’t start and the battery is charged.Check throttle position, and that all battery connections are tight and corrosion-free.

Fuel Flow

Another common suspect of outboard problems is problems with fuel flow. Be sure to top off the tank before you leave and in daily maintenance be checking for leaks and clogs.

ProblemPossible Cause
Outboard won’t start or it sputters to a stop. Fuel flow. Make sure you have gas. Fuel gauges on boats are often unreliable. Top off the tank before leaving the dock.
Outboard won’t start or sputters but you have gas. Check the fuel line for blockage or leaking. Check the filter for clogging.

Temperature Problems

Outboard motors are cooled by water, which means if this system gets messed up for whatever reason, the outboard is in high risk of overheating. Be sure to keep an eye on these problems because temperature problems are a common problem with outboards as well.

ProblemPossible Cause
No water flowing through the “telltale” valve. The cooling system has stopped and immediate care needs to be taken.
There is water flowing through the valve, but the temperature warning light goes off or the motor conks out.The intakes on the motor may be clogged.

Strange Noises

ProblemPossible Cause
Strange noises coming from the outboard such as rattling or shaking. The propeller could be bent or damaged. Slow down a bit until it can be fixed.

Things to Watch For

There are also several things that could be a sign of a major problem going on with your outboard. If you notice these things then it should be checked out by a professional as soon as possible. The website Boat Safe lists out what these signs mean and how to deal with them in their article, “The Life Expectancy of the Marine Engine.”

Exhaust Smoke Color

The exhaust coming out of marine outboard motors should be clear. Any other color is trying to warn you that something is not right. Each color has a different problem causing that tinged smoke.

  • Black Smoke – Black smoke is caused by several things.
    • engine overload
    • restricted air supply
    • fuel injector malfunction (only in diesel motors)
  • Blue Smoke – Blue smoke is a result of when the motors lubricating oil combusts. This can be caused by several things.
    • worn piston rings
    • worn valve guides
    • worn oil seals
    • overfilled air filter (diesel)
    • excess oil in the crankcase
  • White Smoke – White smoke can be caused by several different things.
    • dirty fuel can cause a white vapor
    • water leaking into the cylinder
    • atomized by completely unburned fuel
    • air in the fuel

Oil Appearance Change

The appearance and level of your oil is something that needs to constantly be kept upon. Unattended oil can lead to many severe problems for your motor and you. At the very least, the oil should be checked at least once a day before heading out on the water. But, it improves safety and reliability if the oil is checked before every start of the motor.

When checking the oil there are several things that must be checked. The first thing that must be checked is the level of oil. There always needs to be enough oil in the motor to keep it running and saving it from any problems. Along with that, the consistency of the oil needs to be checked. Boat Safe suggests the following.

“It’s also a good idea to wipe the dip stick clean with your bare fingers and feel the consistency of the oil. Use the paper towel to wipe your fingers. You should rub the oil on the stuck lightly between your thumb and index finger and feel for any foreign particles which could indicate contamination or metal parts failures.”

Boat Safe

When checking the oil it’s important to know when something is wrong, and what that means. When checking the oil it’s important to take notice of the oil level and to be sure that it’s not too high or too low as it can indicate a plethora of serious problems.

  • Oil Level is Too High – This could very well be a sign that water has gotten into the oil somehow. If this has happened, the oil will have a “milky” look to it. If the oil is too high and it’s milky it’s crucial to immediately get it fixed as soon as humanly possible. If there is water in the oil and the motor is turned over there are a lot of things that could go wrong, such as causing a crack to form in the cylinder head, break a piston, or even both.
  • Oil Level is Too Low – If the oil level is too low, this could be a sign that there is an oil leak. If this continues, the motor could end up seizing up, which is very bad as it can lead to more problems. To check if there has been a leak, check the bilge for any oil residue. Sometimes the motor can be sitting extremely low on the bilge, which means that water is always touching it. That can end up leading to corrosion, causing the oil to start leaking out.

How Different Types Last

Of course, there are other things that can affect motors lifespan. There are several different factors that can affect a motor other than maintenance and care. Things like the brand of the motor, the gas type of the motor and several other facts weigh in. Many different boaters have different things to say about which ones are better and last longer. But, that is a personal decision to be made. Here we will go over what some people are saying about these factors, but personal research will have to be done so you can find the outboard motor for you.


There are some very reputable brands of motors, but each has its benefits and drawbacks. For example, on the discussion board Marine Engine several people started discussing how many hours they got on their Honda outboard. Many people were pretty split. Some people were very pleased with what they received while others had problems from the get-go. On the forum, one member said the following.

“I have 2 hondas 25 hp and 90 hp. Gotten very little service always needs repair. Corrosion is a big proble, DO NOT LEAVE ANY FUEL IN CARB. Replaced a 1972 evenrude with a 90 honda, wish I had not. Better luck to you than I have had.”


Another member, Pailolo, was pleased with what he had experienced saying “I got 2250 hrs on my 1997 75hp Honda before it started to burn oil.”

This, of course, is only one brand example. When looking for an outboard brand that will last be sure to do plenty of research.

Gas Type

Boat Safe goes on to talk about the difference between gasoline outboards and diesel outboards.

Gasoline Outboard

Gasoline outboard motors usually can serve for a solid 1500 hours when taken care of on average. It’s said that the first 1000 hours will be peachy-keen with no problems whatsoever. At 1000 hours it will start to exhibit the small problems that often start occurring from old age. These problems, although small need to be addressed immediately as so they don’t turn into big problems.

Diesel Outboard

As for a diesel outboard motor, they last about three times as long as gasoline outboards, coming in at about 5,000 hours of service. If dedicatedly well maintained, some can work up into 8000 hours of work. If you were to boat 200 hours a year, that motor would serve you for 40 years.

According to Boat Safe, diesel motors have a better tolerance than gasoline, accept harsher conditions, but are extremely more expensive. This is worth it though if you know you’re going to be an avid boater for the next 40 years or so. They have incredible longevity, durability, economy, and safety (they’re less likely to catch abrupt fire because diesel has a higher flashpoint than gasoline.

Other Factors

Two-Stroke vs Four Stroke

“Because the speed of four-stroke engines is lower than that of two-stroke engines, these outboards last longer than [two-stroke engines].”

My West Shore

Less Than 100hp

“Once you get over 100hp, you don’t see any outboards from the 70’s and few from the 80’s. Depending on the make/model/salt/fresh etc., you might get 2000hrs or more from an outboard.”


What You Can Do To Prolong Their Life

Even old beat-up motors can fun a long and fulfilling life if properly taken care of. There are several ways that one can prolong the life of their motor. On one blog website, Outboard Motor Oil Blog, they discuss different things that can be done to get the most out of your motor. Some of these things include winterization, regular maintenance, proper mixtures, proper storage, etc.


Just as your boat needs to be winterized, so does your motor. If it is not winterized, often the cold can cause any water left inside the motor to crack or bust parts of the motor. So, there are a couple of things that need to be taken into account when winterizing your boat’s motor according to BoatUS.


Look for a winterizing instruction list in the owners manual of your motor. If there isn’t a checklist available, BoatUS provides a great generalized list that you can use. You will need the following in order to winterize your motor.

  • an aerosol can of fogging oil
  • a fuel stabilizer (gasoline engines) or a fuel biocide (diesel engines)
  • for inboards, a gallon or two of non-toxic propylene glycol antifreeze

What to Do

  1. Freshwater Flush – Flush out your motor with a flushing attachment. Using this clean water to clear the tank can help to rid the motor of any grime and residue.
  2. Empty Fuel Lines and Carburetors – Disconnect the fuel line from the engine while the engine is still running. Then after the engine dies, this will allow the fuel delivery components will be empty. This prevents gum and residue from clogging different lines, jets or injectors.
  3. Fog the Carburetor Intake(s) – Take the fogging out and spray in into the carburetors before the engine runs out of fuel. This fogging oil prevents the internal surfaces of the motor from corrosion.
  4. Draining Cooling Passages – Remove flush attachment and empty out all of the water-holding cells.
  5. Lubricate Links and the Electric Starter Drive Mechanism – Clean visible joints, gears, and pivots with grease.
  6. Drain and Refill Gearcase – Use lubricant specified in the owner’s manual. Fill the oil tank to keep condensation from the inside of the tank.
  7. Touch Up Damaged Paint – Mist the paint or damaged the paint with an anti-corrosion spray.
  8. Drain Fuel Tank and Supply Lines – Don’t start the boat up after winter with old gasoline. Empty out gas towards the end of the boating season.
  9. Stabilize the Fuel – If leaving full fuel in the boat over the winter be sure to dose it with gasoline stabilizer.
  10. Clean and Liberally Lubricate Propeller Shaft – Use the winter to your advantage and take this time to repair propellers and other parts of the motor.
  11. Store Upright – If the motor is stored laying down or on its side water can pool where it shouldn’t undoing the winterization process.

Proper Oil-Gasoline Mixture

With two-stroke motors, it’s important to have the correct amount and ratio mixture of oil and gasoline. Without this correct mixture, the motor fades and wears down much faster than if the correct mixture is used.

Regular Maintenance

Maintenance is also such an important thing to take care of if wanting to prolong the life of your motor. If maintenance is kept up with the boat is it less likely to have major problems later. On Discover Boating, they list out a few things that need to be done to keep up with outboard motor maintenance.

After Every Trip

The following list is a list of things that need to be maintained and checked after every single trip. Not only does this prolong the life of the motor but it provides preventive measures against bigger problems.

  • Often people know to flush out their motors when used in salt water, but it’s a good idea to flush out the motor whether it’s been used in saltwater or freshwater alike. This rids the motor of gunk and residue.
  • In order to pump the water out of the motor, start it up and then let the water pump full out the water. (Stay safe by staying clear of the propeller).
  • While in the process of flushing out the motor be sure to check that the water pump has a good steady water flow. Discover Boating states to check to flow by doing the following.

“Carefully your your finger through the stream of water. It may be warm, but it shouldnt be hot. If the output is not strong, you may have some debris stuck in the outflow tube. Immediately shut down the engine to prevent any overheating and damage. Insert a small piece of wire into the flow tube and work it back it forth. Start the engine again and check the output. If that doesn’t solve the problem, you may need a new water pump.”

Discover Boating
  • After the engine has been flushed be sure to disconnect the fuel line from the motor. Keep the engine running to burn all of the leftover fuel in the carburetor.
  • After done flushing the system and disconnecting the fuel line turn the motor off. If you have a battery switch, switch that off too.
  • Remove the engine cowling. After doing this check for cracks, fuel leaks or water leaks. If leaks are found a boating mechanic needs to be conferred with asap.
  • After a day on the ocean or lake, it is important that everything is wiped down. This removes any excess residue or grime from the day. After it’s been wiped down, spray it over with some kind of anti-corrosive (Discover Boating suggests WD 40 or Quick-Lube.) The parts that are most important to lubricate are anything that moves, sways turns or hinges.
  • Return the engine cowling to its place and wipe it down. It’s a very wise idea to get a cover (plastic or canvas) to protect the outboard from any harm that may come to it in between trips on the water.
  • Lastly, (a long list I know, but each of these things benefits greatly) never reuse fuel. Fresh fuel only. When the season ends and you’re getting ready to winterize the boat and outboard, this should include draining the tanks of the fuel leftover. That fuel then needs to be dropped off at the proper recycling place.

Regular Maintenance

Discover Boating also provides maintenance items that don’t need to happen after every trip but should definitely happen at least once a month if the boat is used regularly. They provide us with the following list of things to keep an eye on.

  • Periodically check the fuel line for cracks and worn spots.
  • Make sure the fuel primer bulb is not cracked and is pliable.
  • Make sure the fuel-line fittings seat properly and don’t leak.
  • Check the clamps on the fuel line for rust or corrosion.
  • Check the fuel tanks for damage and corrosion.
  • Check the tank vent to make sure it aspirates properly.
  • Check regularly for water in the fuel.

Geoff Southworth

I am a California native and I enjoy all the outdoors has to offer. My latest adventures have been taking the family camping, hiking and surfing.

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