Let’s face it: marine engines are asked to perform under the toughest of conditions and in the most unforgiving of environments. They are working in and around a body of water which often also exposes them to salt.

Those two factors alone are tough on any item made of metal, and unlike their automotive counterparts which usually get more consistent use, marine engines are pressed into service whenever their owners have time for them, which is usually not often enough.

When considering the life expectancy of a marine engine, one of the other main things we look at is hours. A gasoline engine simply will not last as long as a diesel engine – period. There is a notable difference between hitting 1,000 hours on a diesel engine vs. 1,000 hours on a gasoline engine.

In this article we’ll discuss the life expectancies of both gas and diesel marine engines plus tackle the question of whether a 1,000-hour gasoline engine boat may still be a great buy.

Gasoline EnginesGasoline vs diesel boat engines

Gasoline marine engines, on average will run for about 1,500 hours (which is about half that of a car) before needing an overhaul. This is considerably less than a diesel, however one advantage of gasoline engines is that they are much cheaper to purchase and to re-power.

With gasoline engines, it is important to be very proactive and to stay on top of service and maintenance. It is also imperative that all small issues be addressed and not neglected. Remember, “small things will lead to big things.”

A gasoline engine should be run regularly for maximum longevity. Of course, this doesn’t always happen in real life. Many boaters take their new boat out a few dozen times in the first year. This may taper off to a few outings a year for events like Memorial Day weekend, some summer weekends and Labor Day weekend. The rest of the time the boat – and its gas engine – sit neglected. This non-use added to the strain of exposure to the moist and corrosive marine environment has the potential to shorten the life of a gas engine.

Diesel Engines

Diesel engines are significantly more expensive than gas because they are built to tighter tolerances and can stand much more abuse than their gasoline counterparts. Diesel engines when maintained properly can give you 6,000 to 8,000 hours of good use before needing a major overhaul. This means, some diesel engines can easily last the full lifetime of the boat.

When making a choice of engine type, most boaters who choose a diesel do so for their durability. Other reasons include safety and/or economy. Diesel fuel is not as volatile as gasoline and does not explode. Your fuel budget goes further with diesels since they are also much more economical to operate.

Finally, diesel engines are more forgiving of non-use than gasoline engines, although they too prefer to be run more frequently and for long stretches at a time. As with gas engines, since diesel engines are also made of metal, the moisture and salt of the marine environment still take their toll.

The 1,000-hour gas engine boat – to buy or not to buy?

Now that we’ve compared the pros and cons of gas vs diesel, it’s time to tackle an important question that many would-be boat owners come across as they are shopping:

“Is it worth it to buy a gas-powered boat with 1,000 hours on the engine?”

Although we’ve all heard cautionary tales, the 1,000-hour gasoline boat out there on the market can in fact be a “diamond in the rough.” A boat with around 1,000 hours on its gas engine may sometimes be a bit difficult for the owner to sell which in turn can mean a great deal for a buyer.

Should you consider being that buyer? Let’s go over what to look for in a potential 1,000-hour gas boat.

What to look for

First, pay particular attention to the service and maintenance records. If it has around 1,000 hours and it has good service and maintenance records, it may just be a great buy. Examples of these boats are those owned by licensed captains where the boat is used as part of the owner’s profession. Here, the captain is usually on top of all service and maintenance because not only is the captain on the boat on a regular basis, but the boat is also the captain’s bread and butter. That means that he/she has had a vested interest in proper upkeep.

Another example to look for would be the owner who doesn’t have time to take his boat out often but has no issue opening up his wallet up as needed for preventive service and repairs. In this case, you may see a rather large folder or binder with immaculate record keeping that goes back to the first oil change and winterization. Here you will plainly see that the boat has been very well maintained and taken care of. Good yards do good work which means they generally catch anything that requires attention as part of their services.

A final example would be active fisherman or mechanically aware boaters who just take great care of their engine.

What to inspectDiesel-Marine-Engines

Once you have identified a potential candidate vessel, there are two major things you can inspect to gauge the condition of the engine. This will help you decide if it’s worth moving on to doing a sea trial and getting a surveyor to do a full inspection.


One thing you can do while checking out a boat is to inspect the oil via the dipstick.

  • Feel the consistency. Is it smooth or does it feel like particles and grit are contaminating it? Any metal filings or very small pieces of metal could mean trouble.
  • When looking at the oil, what color is it? Milky oil is a sign of water intrusion into the engine – another bad sign.


Exhaust smoke should be mostly clear. If there is a noticeable color to the exhaust smoke, this could be a warning that something is wrong.

  • White smoke usually means water. This could be water vapor coming from some kind of leak that has made its way into the cylinder.
  • Blue or blue-grey smoke usually is produced in a high hour and tired engine. This color smoke may indicate that something such as valve guides, piston rings or oil seals is extremely worn.
  • Black or dark smoke usually occurs when the engine is overloaded. Think Jaws during the last scenes when Quinn pushes his boat full power while hooked onto the shark. It can also mean a bad fuel injector, unburned fuel, or even a restricted air supply somewhere in the system.

Note that there are many issues that can be addressed as part of the sale or as a coupon so never back out before asking questions…especially if it is a boat your have had your eye on awhile.

Final Thoughts

Just because you see that 1,000-hour meter don’t turn and run – do your homework. There are some gas boats out there that have 6,000 hours on them and are still out every weekend. That is because they are taken care of and serviced regularly.

A careful review of service and maintenance records along with an inspection of the oil and exhaust may just lead you to a steal of a deal on a 1,000-hour gas boat.