Inboard to Outboard Conversion: Everything You Should Know

July 28, 2021

We have been getting a lot of questions about inboard to outboard conversions recently. Maybe it’s the ‘grass is always greener on the other side’ mentality, but it seems fishermen who have inboards are always wondering what owning an outboard would be like. So we figured, why not answer a few of the most common questions on inboard to outboard conversion?

In this article, we’ll discuss how to perform an inboard to outboard conversion, how much they cost, whether they are a good idea, the pros and cons of inboards vs outboards, and much more. Doing an inboard to outboard conversion is a ton of work, but there are clear benefits to having an outboard. When you are done reading this article, you’ll have a better understanding of if it is worth it for your situation.

Let’s get started.

Inboard to Outboard Conversion: Can You Do It?

If you were still wondering if you can convert an inboard motorboat to an outboard motorboat, the answer most of the time is yes. Is it a good idea? It depends! There are a lot of factors you have to consider when deciding to do an inboard to outboard conversion.

In order to add an outboard motor to your inboard boat, you’ll need to check the transom to make sure it is structurally sound and strong enough to add a heavy weighing motor. We recommend getting this done at a boat shop or with a fabricator who is familiar with boats.

Next, you’ll need to make sure there is room for glassing an I/O plug in the transom and mounting a hydraulic steering system. You’ll need to add a new steering system to the boat since the old inboard prop or jet pump steering won’t work anymore. You may need to adjust or make new bunk brackets on your trailer as well.

After these steps, you’ll need to buy an outboard motor and mount it to the transom. While these steps don’t sound super complicated, it will be an expensive proposition. And on top of that, you may end up with a boat that performs significantly worse than before. We’ll get into that in a second.

Inboard to Outboard Conversion: Is It Worth It?

Now that you’ve figured out if you can do an inboard to outboard conversion, it is time to ask yourself if it is worth it. Here are all the things you should consider.

The first thing you’ll need to consider is how the telemetry of your boat will change with a heavy motor added to the back of it and the effective length increased with the addition of a setback bracket or offshore bracket.

This will most likely change how your boat handles – and usually not for the better. You may need to add weight to the bow of your boat to prevent it from porpoising or having water splash over the transom in the back. 

Inboard boats (like Boice jet boats) are known for having great handling since their weight is more evenly distributed. Removing the inboard engine and adding an outboard completely changes their weight distribution, and will change how they handle.

How Much Does It Cost to Convert an Inboard to Outboard?

Another big thing you should consider is how much an inboard to outboard conversion is going to cost. After talking to several of our friends who have done it or looked into out how much it would cost, we estimate an outboard to inboard conversion would cost between $25,000 to $35,000 when you factor in buying a new motor and all the labor associated with doing the transformation.

If you can do the labor yourself it would probably cost between $15,000 and $20,000.

Advantages and Disadvantages of Inboard Motors

If we take a step back from doing an inboard to outboard conversion, it makes sense to consider the advantages and disadvantages of inboard motors. Should you even be considering an inboard to outboard conversion? Are inboard motors actually worse off than outboards? Let’s consider the pros and cons.

Advantages of Inboard Motors

  • They usually have more power than outboard boats around the same size. Most inboard motorboats have 200 to 300 horsepower, while outboards of similar size usually only have around 100 horsepower. This makes inboard boats more effective for water skiing, wakeboarding, and tubing. When you are towing someone behind your boat for water skiing, you need to have enough horsepower to pull them out of the water and up onto a plane quickly.
  • If your inboard motor boat is a jet boat, then it can operate in very shallow water. Probably the biggest advantage jet boats have over outboards or boats with props is that they can operate safely in water conditions prop boats can’t. Outboard motors would most definitely hit the bottom at this deepness and cause major damage. This makes jet boats great for river water sports and river fishing. But you should still consider getting a keel guard.
  • Inboards sound better. Yes, this is subjective and doesn’t really matter, but we think inboard boats sound much better than outboards. This is because they typically have larger car engines inside them (like a V6 or V8).

Disadvantages of Inboard Motors

  • They are often less efficient than outboards. While a V6 or V8 engine sounds better than a four-cylinder, they almost always use more gas. This means that operating an inboard boat usually is more expensive than an outboard.
  • Inboard motors are harder to perform maintenance on. Inboard boats usually have their motor built into the hull of the boat, and it’s much harder to perform maintenance on. When you need to change the oil you have to go into the boat and do it there – which means it’s much messier and a hassle. If the motor breaks, it’s also much more expensive to replace (since it is usually a car engine).
  • They are harder to clean than outboards. If you do decide to take your inboard boat in saltwater, you’ll need to take it out in freshwater soon after to flush the engine system of salt. If you don’t it will corrode and break much faster. With an outboard, you can simply flush the system with a hose and boat earmuffs at home (or at your own convenience). It’s much less of a hassle.

FAQs

Are Inboard Motors Bad?

It depends on what you are using the boat for! As we mentioned in our pros and cons list above, there are many reasons why both outboard and inboard motors are better than one another. If you plan on fishing in shallow water or enjoying water sports, then we think inboards are a great option.

Do you like having a bigger engine in your boat? Inboards are also probably what you’ll want. 

If you plan to fish in saltwater a lot and prioritize ease of use for maintenance then an outboard boat is probably your best bet. It all comes down to what you plan to use the boat for and your personal preference!

How Long Do Inboard Motors Last?

Again, it depends on how you use your inboard motor and if you treat it well. If you do what you are supposed to (like flushing the engine frequently and staying up on maintenance), most inboard motors last at least 2,000 to 3,000 hours.

We’ve had friends who have put over 5,000 hours on their inboards, however, so it really just depends on how well you treat them and a little luck.

Can You Run an Inboard Motor in Saltwater?

Absolutely! You just need to be sure to flush the engine system soon afterward by taking your boat into freshwater. If you do this, you have nothing to worry about. If you don’t, your engine system will quickly corrode break.

Why Are Boat Engines So Unreliable?

There is a common misconception that boat engines are less reliable than other types of engines. In reality, they are just as reliable but are treated much worse than other types of engines. 

They aren’t maintained as regularly as car engines, they are allowed to sit unused for months at a time, and are around water way more. All of these factors cause them to break more frequently than their car counterparts. 

If you treat your boat engine with respect and use/maintain it as recommended, it will be just as reliable as any other type of engine.

Conclusion

Performing an inboard to outboard conversion will require a lot of time and money, but for some folks, it can be a really fun project. As long as you know what you are getting yourself into and how much it is going to cost, you can definitely make the change.

We hope you found this article useful for learning more about inboard to outboard conversion. If you have an experience you would like to share with the community or other questions about conversion, let us know about it in the comments below.

Happy Hunting!

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