What are MAG Side and PTO Side On a Jet Ski? [Explained]

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Are you wondering what MAG Side and PTO Side mean on a jet ski engine? In a nutshell, the meaning of these acronyms are as follows:

  • MAG Side: MAG stands for “Magneto” (refers to the front side of the engine)
  • PTO Side: PTO stands for “Power Take Off” (refers to the rear side of the engine)

If you want to find out more about this topic, keep reading. We at JetDrift have compiled all you need to know into this post!

What are MAG Side and PTO Side On a Jet Ski?

If you read about jet ski engines, you will often come across the following terms “MAG” and “PTO” sides. These terms actually characterize the two sides of the engine.

The term PTO here stands for: “Power Take Off,” which refers to the rear side of the engine. As the name suggests, this is where engine power takes off from the crankshaft.

As a rule of thumb, jet ski engines are always mounted longitudinally, with the PTO side facing back. This is because jet skis feature a “direct drive system,” meaning that engine power is transferred directly towards the impeller with a driveshaft.

(Sea-Doos feature a one-piece driveshaft sealed by a carbon ring, while Yamaha and Kawasaki jet skis have a two-piece driveshaft attached to the crankshaft via a coupler.)

To make this connection as simple as possible, the crankshaft on jet skis must point towards the jet pump. This is why on jet skis the crankshaft side (a.k.a. PTO side) of the engine is always facing towards the stern of the vessel.

In contrast, the MAG side is the front side of the engine.

The term “MAG” stand for Magneto, which refers to the flywheel magneto. This unit is actually the jet ski’s generator, providing electricity for the ignition and the electrical system.

Since the flywheel is also driven by the crankshaft, it has to be placed on the opposite side of the PTO side.

This is why the magneto “MAG” side where the electricity is generated always refers to the front side of each jet ski engine.

What are MAG and PTO Cylinders on a Jet Ski?

For easier identification, these terms (Mag and PTO) are also used to identify the cylinders and the carburetors on twin jet ski engines.

The general rule is that the PTO cylinder refers to the rear cylinder, while the first cylinder is the MAG cylinder. Keeping with the same analogy, the carburetors can also be referred to as “MAG side carb” and “PTO site carb.”

Please note that these terms are inherited from vintage jet skis, which were typically powered by 2-stroke, 2-cylinder engines. (They also featured one or two carbs depending on the model.)

In contrast, today’s jet skis are powered by 3 or 4-cylinder, 4-stroke engines, so these terms are no longer really used for the cylinders and carburetors.

Takeaways

As a takeaway, we’ve answered the most common questions on this topic.

What Does PTO Stand for on a Jet Ski?

PTO on a jet ski stands for “Power Take Off.”

What Does MAG Stand for on a Jet Ski?

MAG on a jet ski stands for “Magneto.”

What are PTO Side and MAG Side On a Jet Ski?

The PTO (Power Take Off) is the rear side the engine where the crankshaft transmits power to the driveshaft. In contrast, the MAG side is the front side were the flywheel magneto is attached to the engine. These terms are also commonly used for identifying the cylinders and the carburetors on vintage 2-cylinder jet ski engines.

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