Mercury – Quicksilver Gear Lube Pump Adapter | Maintenance Tools | Marine-Grade Construction | 883704K03

Overview

If you’ve ever serviced your own lower unit, you know there’s something satisfying about doing the job right — clean pump strokes, no stripped threads, no leaks dribbling down the skeg. It’s one of those maintenance moments that makes you feel connected to your boat. A simple, reliable adapter turns that task from a headache into an easy routine.

This Mercury Marine part brings that confidence to the job. It gives you the peace of mind that your gear lube pump will thread in smoothly and seal tightly, so you can focus on taking care of your engine instead of fighting with mismatched fittings.

Key Features

• Converts a standard 3/8-16 gear lube pump tube to fit 8x1.25 metric gear lube fill holes
• Marine-grade metal construction built for durability and steady threading
• Precision-machined threads ensure a tight, secure seal during gear lube service
• Compact, corrosion-resistant design for long-term use in marine environments
• Installs quickly and easily with hand tightening

Engine & Boat Compatibility

• Fits Mercury and Mariner outboards:
  • 4–5 HP (1987 and newer)
  • 4/5/6 HP FourStroke
  • 225 HP EFI FourStroke
  • 2005+ 8/9.9 HP FourStroke
  • 2006+ 25/30 HP EFI FourStroke
  • 15/20 HP FourStroke (351 cc)
• Works on all Mercury and Mariner outboards of Japanese origin
• Compatible with all outboards requiring an 8x1.25 metric threaded gear lube fill port
• Includes compatibility with Nissan, Yamaha, Tohatsu, and Honda outboards using the same metric threading
• Ideal for anglers, weekend boaters, tender owners, and anyone doing their own gear lube changes

Performance & Practical Benefits

A good adapter shouldn’t make you think — it should just work. That’s exactly how this Mercury Marine part feels the moment you thread it into a metric gear lube port. The connection seats smooth and tight, giving you that secure, locked-in feeling without wobble or guesswork.

There’s no slipping, no cross-threading, no “almost fits.” Just a clean, steady seal that lets you pump gear lube exactly where it needs to go. The precision threads prevent leaks during pumping, and the corrosion-resistant finish holds up against salt, moisture, and years of marine use.

If you’ve ever serviced multiple engines — especially a mix of American and Japanese designs — you know how useful this adapter is. It keeps your maintenance clean, efficient, and frustration-free. And once you’ve used it a few times, it becomes one of those small tools you don’t leave the dock without.

Why Buy OEM

There are plenty of cheap adapters out there, but very few deliver the fit and durability of a true Mercury Marine part. With part number 883704K03, you get threading that feels right the first time, every time. No soft metal. No poorly cut threads. No leaks.

OEM means:

• Built to exact Mercury standards
• Long-term reliability
• A perfect match for Mercury, Mariner, and Japanese-origin models
• Peace of mind during every lower unit service

If a fellow boater asked which adapter to trust, this is the one I’d recommend without hesitation. It simply gets the job done correctly — and that’s what counts.

FAQ

Q1: Which engines does the Gear Lube Pump Adapter 883704K03 fit?

It fits Mercury and Mariner 4–5 HP (1987+), 4/5/6 HP FourStroke, 225 HP EFI FourStroke, 8–30 HP FourStroke models (various years), and all Japanese-origin Mercury outboards.

Q2: What makes this adapter better than aftermarket versions?

The precision machining and marine-grade durability ensure a smooth fit and reliable seal every time.

Q3: How do I know if this is the right adapter for my setup?

If your gear lube fill hole is metric 8x1.25, this is the correct adapter.

Q4: Can I use it in both saltwater and freshwater environments?

Absolutely — the corrosion-resistant metal is designed for harsh marine conditions.

Q5: Is installation straightforward?

Yes. Hand-thread it onto your pump tube, connect it to the fill port, and you’re ready to pump.