Make Your Jet Boat’s Engine Even Faster
There are a range of ways in which you may make your boat go faster, but making your boat's engine go faster is a very different topic. But the character of marine engines is such that revving up your powerplant beyond its present level is a topic unto its own.
All engines are designed to turn up to some specified RPM range. Before we accept this conversation any farther, we must point out that making any alterations to your engine that induces it to rev higher than its designed wide-open throttle speed generally voids the guarantee. As a result, most people who want to make their engine quicker do not do so until a motor is currently out of warranty (though if money is no object, have it). The next fact to think about is that manufacturers design their search engines and all of the parts connected to them with this RPM range in mind. Push past it and there's a really good chance something -- or what -- will burst. Catastrophic failure isn't an unreasonable expectation and those who strive to earn their engine quicker need to understand they may well receive a very short period of enjoyment before the spring which you put inside that engine measure is totally sprung. The bottom line? Fine tune in your risk, and realize that the risk is rather significant.
Quick Fixes for a Faster Engine
First let's take a look at the less risky ways to get search engine spinning faster. There are three quick and easy modifications you may make to your boat, which will allow an engine that's not quite hitting its peak to run somewhat faster: Shedding weight from the ship, changing the propeller, and (in the case of outboards) jacking up the engine.
Removing weight from your boat is cost-free, and can be very effective at making your engine faster. The problem is often simply as the years go by, we add an increasing number of junk onto the boat. On top of this, multiple layers of bottom paint or soaked coring can add to a boat's weight. In fact, the same boat might weigh 10 or perhaps 20 percent more than it did when you first found it, either five or 10 decades ago. The internet result? Your engine, which may have struck 5000 RPM whenever the ship was brand new, now only matches around 4500 RPM as it struggles to overcome all that excess weight. A couple of hours spent removing gear, soda-blasting an over-painted underside, and replacing areas of saturated heart and find that engine running the way it was supposed -- faster -- even though it could be operating now.
Altering the propeller is another means to get the powerplant turning greater RPM. As a general rule of thumb, switching to a propeller with an inch pitch (if you are unsure of precisely what propeller pitch is, read Knowing Propeller Pitch) will cause the engine to flip about 200 RPM quicker. Note: you might also gain boat speed through swapping propellers if you currently have a aluminum prop. Because stainless-steel propellers flex less than aluminum, trading out for one can increase boat speed by several. This isn't exactly creating your engine faster, but if an increase in rate is your final goal you'll certainly want to take this reality into account.
Jacking the engine up is a method outboard owners can utilize. It is not inexpensive, since you will want to pull off the engine the ship, mount a jack plate to the transom, then mount the engine to the jack . Do this, however, and you can raise the engine (while the boat's running, if you find yourself with a hydraulic jack plate) to get as much of this lower unit from the water as possible. Less lower unit at the water means less drag, so that your engine can spin just a hair quicker and the ship will move along at a slightly quicker clip.
High Risk/High Reward Methods to Make Your Engine Faster
If you're willing to risk your motor well-being, there are some mechanical alterations you may make to make it running faster. While they are not available for all engine models and makes, bolt-on superchargers are on the market for a number of marine powerplants. The supercharger packs more air and fuel into the engine cylinders in a procedure called forced induction, boosting horsepower output by around as much as 50 percent. Remember: you will likely void any warranties which may be on the motor and there's a good chance that you will substantially reduce its lifespan. However, it is going to go quicker.
It's important to also point out that only bolting on the supercharger isn't the only thing you will need to do to exploit all this additional power. You will also need to modify your propeller and potentially even the reduced unit, as a different gear ratio may be required. Supercharging isn't inexpensive, either. Whipple Superchargers, a few of the very popular on the current market, start at $5,395 and range all the way up to over $11,000. They are available for a number of gas inboard and stern drive powerplants, but due to the tight nature of an outboard's cowl, can not be added to this type of engine till they're designed to run with a supercharger at the first place (like the Mercury Verado 350 and 400R).
A less dramatic but also marginally less risky approach to earn your engine quicker would be to do an ECU (engine control unit) upgrade. The ECM is what controls the time, spark curve, and gas and air leaks, in the majority of modern engines. Basically, it's the digital brain that tells the engine and how to fire. It can be replaced or"reflashed" to boost horsepower in inboards, stern drives, and outboards by a wide array -- as small as five percent in some instances, and up to 40 percent in others. And such as the supercharger it could also require re-propping, depending on how significant the energy gain is and how much maximum RPM increases.
Imagine if all these improvements, modifications, and changes sound like a little more than you are willing to manage? Perhaps picking a brand new engine which goes uber-fast in the first place is your best move for you.