repair your generator

To repair your generator or to replace your generator…that is the question.

It’s a dilemma many generators of a certain age present to their owners. The genset prompts so many service calls that Joe the mechanic feels like a member of the family, and you’re beginning to question its reliability. Should you replace your generator? Should you replace it? Here are a few points to consider when making your decision.

How’d we get here?
Before deciding whether to repair or replace the ailing generator, let’s look at how we likely got to this point and, hopefully, how we can avoid a repeat in the future. “One of the most common causes of problems with generators is lack of use,” says Tom Sutherland, director of sales and marketing for Westerbeke Corporation. “It’s not unusual
to talk with customers having problems only to discover that the root cause is infrequent use.” In other words, a two-year-old generator with 1,000 hours of operation is usually less susceptible to trouble than a two-year-old generator with 100 hours of use.

While gasoline and diesel generators have different characteristics, typically the more a generator is used (assuming proper maintenance, of course), the more likely it will provide better performance and enjoy a longer service life. It’s important to note that engine and cooling system components (seals, fuel pumps, heat exchangers, etc.) also tend to deteriorate and fail sooner with minimal use.

Operating in salt water versus fresh water is also a factor. Salt water takes a greater toll on your generator, particularly the cooling and exhaust systems. Corrosion can also be a major issue for units operating in salt water. Moisture damage can occur not only to the unit’s exterior but also to the generator’s electrical systems (both AC and DC).

Units that have suffered extensive moisture damage should likely be replaced. Even if initial repairs appear to be successful, water can migrate along wires and cable runs causing corrosion and future reliability issues, such as those dreaded “intermittent problems” which can take so much time and money to track down.

Factors to consider: In general, if you’re facing major engine or electrical repairs to a generator that’s more than five years old, replacement might be a better option. Depending on the extent of the fixes, you may find that the cost of replacement versus repairs is not that far apart.  There could be other existing factors that can effectively reduce this gap even further. Here are some to think about:

Reliability: Is your current generator trustworthy or do you silently mouth a prayer each time you hit the start button? If your generator (as Captain Ron puts it) “loves her oil
same as a sailor loves rum” or is in need of significant repairs, now may be the time to replace.

Parts and service availability: Locating parts for an older, outdated generator can be an ordeal, as well as finding someone with the knowledge to work on it.

Old school versus cutting-edge: Replacement allows you to enjoy the latest technology—from greener efficiency and fuel economy to less vibration and quieter operation— typically in a smaller, lighter package. Even if you crunch the numbers and can save a few bucks by completing a major overhaul of your current unit, you’ll still wind up with an old-model generator—one without the golden umbrella of a factory warranty.

Long-term goals: Consider how long you intend to keep the boat, as well as your future plans (such as extended cruising). For those thinking about sailing off into the sunset in search of paradise and tropical drinks, the peace of mind that comes with replacing an aging, questionable generator can be a significant factor.

Other vessel upgrades: If your future plans include installation of new, power-hungry equipment (another airconditioning unit, gyrostabilizer, etc.), your existing generator
may not be able to meet the additional power requirements.

The bottom line: The decision to repair or replace can be boiled down to comparing the price of installing a new generator with the cost to fix your current unit and keep it running reliably.

For an older generator that continuously needs improvement or provides questionable service, think about a replacement. However, “if the set is used frequently,  operated properly and well-maintained,” says Sutherland, “the occasional non-maintenance-type repair is expected and worth the investment.” Just keep in mind that many non- disposable components (water pumps, heat exchangers, cooling hoses, mounting isolators, and exhaust systems) do have a finite service life and will need to be replaced at some point.

Choose wisely: If you decide to replace your generator, always consult the manufacturer or an authorized representative as part of the selection process to determine which model best suits your current (and future) power needs. A generator that’s too small will be constantly laboring to meet demands, leading to poor performance and a shorter service life. Conversely, installing a generator that’s too large will lead to “underloading” problems, such as carbon buildup in the engine, incomplete fuel combustion, and overall inefficient operation.


Cummins Onan



Northern Lights




By Frank Lanier, Southern Boating September 2017

  1. It helped a lot when you mentioned how you should take the time to consider replacing your generator if it is older than 5 years. I understand that doing some research and comparing several companies can help you find the best way to deal with your generator. We are planning on getting a generator and want to make sure we know how to properly care for it and when to replace it, so I’m glad I found your page.

  2. I like how you pointed out that locating parts for an older generator can be an ordeal, and it can be difficult finding someone with the knowledge to fix it as well. My husband and I are thinking about installing a generator at our home and I think it would be best if we could find a newer one that will be easily repaired in the future. This is great information to help us in our search for the perfect generator.

  3. I always prefer to replace it just because if it broke down once, it will probably break down again. I’ve been in a pickle too many times from a busted generator. Great share btw!

  4. Wow, I had no idea that the type of water you use will affect your generator so much. My uncle runs a small trucking company and mentioned his genset has been having a lot of issues lately. I’ll have to ask him if he had to use salt water recently since it takes a greater toll on the generator’s cooling and exhaust systems.

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