Mercury – Stern Thruster Top Assembly for Pontoon JPO (No Cover) | Control System | 8M4509077

Overview
This stern thruster top assembly is part of the Joystick Piloting setup used on single-engine pontoons. It helps the stern make controlled sideways moves, which takes a lot of stress out of docking a wide pontoon in wind or current. This version is the top assembly only, without the cover, and is meant for service or replacement work. Once installed, the stern responds more predictably during slow maneuvering.

Key Features
 • Stern Thruster Top Assembly – Core upper section of the stern thruster unit.
 • JPO Integration – Works directly with Joystick Piloting for Outboards.
 • Single-Engine Pontoon Design – Built for large pontoon platforms using one outboard.
 • Smooth Stern Control – Helps the rear of the boat slide cleanly into position.
 • Service/Replacement Part – Top assembly only, without the exterior cover.

Engine & Boat Compatibility
 • Joystick Piloting for Outboards
 • Single-engine pontoons
 • Digital Throttle and Shift
 • Thruster-equipped systems

Performance & Practical Benefits
On the water, a functioning stern thruster helps the back of the boat track straighter when wind or chop starts pushing you around. It makes it easier to square up with a dock or hold the boat steady while dealing with lines. Movements feel smoother and less rushed, which is especially noticeable on bigger pontoons that don’t always behave well at idle. With this assembly in place, slow-speed handling feels more relaxed and controlled.

Why Buy OEM
OEM thruster parts match the JPO system’s tuning, so commands flow cleanly between the joystick, stern thruster, and outboard. Mercury’s calibration keeps reaction and timing consistent from season to season. It’s the dependable choice when you’re replacing thruster components.

FAQ
Q1: How do I know if my stern thruster top assembly needs replacement?
A: Weak, inconsistent stern thrust or noisy operation often points to wear in the top assembly.

Q2: Does it require calibration after installation?
A: Yes, the JPO system usually needs a quick calibration to sync everything.

Q3: Is it suitable for saltwater?
A: Yes—just rinse the area and follow normal thruster maintenance.

Q4: Anything to check before installing?
A: Make sure the existing housing and wiring are in good shape, since this is the top assembly only.

Q5: What if the thruster reacts slowly after installation?
A: That’s typically a calibration or power-supply issue rather than the top assembly itself.