Mercury – Trim Switch | Outboard Control System | Marine-Grade Polymer | 8M0042300

Overview

Every boater knows the feeling—you ease into the throttle, the bow begins to lift, and with a simple tap of the trim switch, the hull settles into that perfect running attitude. It’s a small motion, but it completely changes how your boat handles the water. A trim switch isn’t just a button; it’s control, comfort, and confidence right at your fingertips. And when that switch starts to fail, you feel it immediately.

That’s why the Mercury Marine part number 8M0042300 trim switch matters. It’s the kind of part you replace not because it’s exciting, but because you know how important it is when conditions turn unpredictable. This switch feels solid, responsive, and reliable—exactly what you want when you’re trimming the engine while skipping through chop or easing into a tight marina.

Key Features

• Designed to control engine trim with smooth, responsive operation
• Built with durable marine-grade polymer housing
• UV-resistant, corrosion-resistant, and formulated for harsh marine exposure
• Engineered for more than 20,000 up and down cycles
• Manufactured to Mercury Marine’s original equipment specifications
• Fits a wide range of Mercury outboards across multiple generations

Engine & Boat Compatibility

• Works with Mercury outboards including:
  • 25–60 horsepower carbureted FourStroke models
  • 40–60 horsepower EFI models
  • 60R EFI FourStroke engines (1C453840 and up)
  • 1.5L 75–115 horsepower TwoStroke engines
  • V150–V200 EFI TwoStroke series
  • 2.5L 150–225 horsepower TwoStroke engines
  • 4-cylinder 35–175 horsepower EFI FourStroke engines
  • 3.0L 200–250 horsepower TwoStroke models
  • L4 and L6 Verado engines, 200–350 horsepower
• Common on fishing boats, offshore center consoles, pontoons, runabouts, and bass boats
• Suitable for single-engine and multi-engine configurations

Performance & Practical Benefits

A good trim switch should feel almost effortless—and this one does. The button motion is crisp and predictable, giving you that instant, “Yep, that’s right” response every time you use it. Whether you’re trimming up to clear shallow flats or trimming down to flatten the bow for an early-morning run, the action feels smooth and controlled.

Because this switch is built for the marine environment, it holds up against salt spray, sun exposure, and the constant vibration of a running outboard. It stays tight, stays clean, and stays responsive even when you put a lot of hours on the water. Installation is straightforward, and once it’s in place, it blends right in like it’s always been part of the helm.

Most boaters notice the difference immediately. The engine responds cleaner, the button doesn’t hesitate, and trimming starts to feel like a natural part of driving again—not something you have to fight with.

Why Buy OEM

OEM parts aren’t just about brand loyalty—they’re about knowing your gear will work when you need it. This Mercury Marine part is built to the same standard as the components installed at the factory. It fits perfectly, performs exactly as intended, and lasts far longer than many aftermarket switches.

You won’t be guessing about wiring, housing quality, or long-term durability. You’re getting something that’s been tested, vetted, and proven in real-world marine environments. For a part as essential as trim control, that peace of mind is worth a lot.

FAQ

Q1: Which engines does this trim switch fit?

It fits a broad range of Mercury outboards from 25 horsepower FourStroke engines up through L6 Verado models.

Q2: What makes it better than aftermarket switches?

OEM switches offer better sealing, smoother button action, and much longer cycle life—especially in harsh environments.

Q3: How can I confirm this is the right replacement?

Check your outboard’s serial number range or compare the part number in your owner’s manual.

Q4: Can it be used in saltwater?

Definitely. It’s designed to resist corrosion, UV rays, and saltwater exposure.

Q5: Is installation easy?

Most boaters find it straightforward with common tools. Wiring connectors match factory harnesses for a clean fit.