Mercury – Marine Rotor for GM V6 (Delco HEI) | Ignition | 8504851 / 8M0062084

Overview

If you’ve ever worked on a marinized GM V6 with a Delco HEI ignition, you know the rotor takes a beating. It sits in a hot, cramped spot, shaking around while the boat moves, and dealing with moisture every single trip. When it starts to wear out, the engine usually shows it fast—little hiccups at idle, a miss when you throttle up, or that uneven feel you can’t quite ignore. This rotor is built for that kind of abuse and holds up a lot better than the cheap automotive ones that tend to crack or arc out in a marine environment.

Key Features

 • Made for GM V6 Marine Engines – Fits Delco HEI ignition systems used in many MerCruiser-style setups.
 • Tough, Lightweight Design – Helps the rotor survive heat and vibration without splitting.
 • Coated Brass Blade – Cuts down on RFI noise that messes with radios and electronics.
 • Use with Cap 85048T2 – Designed to pair with the matching Quicksilver distributor cap.
 • OEM-Level Reliability – Delivers steady spark and long service life.

Engine & Boat Compatibility

 • Marinized GM V6 engines
 • Delco HEI ignition
 • Sterndrives and inboard packages
 • Quicksilver distributor cap 85048T2

Performance & Practical Benefits

Swap in a fresh rotor and the engine usually smooths right out. Idle steadies, cold starts get easier, and throttle response feels more honest. Old rotors like to break down from heat and moisture, which leads to weak spark or random misfires—problems this rotor clears up immediately. It’s a simple part, but it makes the engine feel more “dialed in.”

Why Buy OEM

OEM marine ignition parts are built for hot, wet, vibrating engine bays—conditions that destroy bargain rotors. Fitment is right, the materials don’t crack early, and the coated blade doesn’t create electrical noise. It’s the kind of part you replace once and don’t have to think about again.

FAQ

Q1: How do I know the rotor is going bad?
A: Misses at idle, hesitation when you throttle up, hard starts, or inconsistent spark.

Q2: Should the cap be replaced at the same time?
A: If the terminals look pitted or corroded, yes—it saves you from doing the job twice.

Q3: Does the coated blade really help?
A: Yes, it cuts down interference that can affect radios and gauges.

Q4: Is the job difficult?
A: Not at all—pop the cap off, lift the old rotor, press the new one on.

Q5: Will this hold up in saltwater use?
A: Yes, it’s built for marine heat and moisture, not automotive conditions.

• Supersessions
  804424, 850485, 898253012, 8M0062084, 8M0062084