Sierra 18-5879 Yamaha 40-90Hp 2 Stroke Solenoid
Sierra 18-5879 Yamaha 40-90Hp 2 Stroke Solenoid — Product description
Keep your Yamaha 2-stroke outboard humming smoothly across the water with this precision-engineered fuel solenoid. Designed as a direct replacement for worn-out components, it ensures reliable fuel flow control, preventing those frustrating no-start moments or fuel leaks that plague older engines. Whether you're prepping for a weekend fishing trip or maintaining your classic rig, this solenoid delivers the dependable performance Yamaha owners expect without the hassle of sourcing originals.
Seamless Compatibility with Popular Yamaha Models
This solenoid fits a wide range of 2-stroke Yamaha outboards, making it a go-to upgrade for enthusiasts restoring or repairing these powerhouses:
- 40hp models (1984-1988)
- 50hp models (1984-1988)
- 60hp models (2001-2006)
- 70hp models (1991 to present)
- 90hp models (1984-1991)
Before installing, double-check your engine's serial number against Yamaha's model guides to confirm compatibility—many of these share the same solenoid footprint for easy swaps.
Why This Solenoid Stands Out: Features That Matter
Crafted from durable, corrosion-resistant materials built to withstand saltwater exposure and constant vibration, this unit features:
- Precision actuation: Electromagnetic coil responds instantly to your ignition key, opening the fuel valve for quick starts and shutting off cleanly to avoid flooding.
- Leak-proof seals: High-grade O-rings and plunger design eliminate drips that lead to fire hazards or carburetor gunk.
- Compact and robust build: Matches OEM dimensions for bolt-in installation, weighing just enough to stay secure without stressing mounts.
- Extended lifespan: Tested for over 100,000 cycles, outlasting generic imports that fail prematurely in marine environments.
Unlike flimsy aftermarket knockoffs, it's engineered to handle the ethanol-blended fuels common today, reducing varnish buildup inside the solenoid body.
Spot the Symptoms: When to Replace Your Solenoid
Listen to your engine—it's telling you something. Common red flags include:
- Engine cranks but won't fire up, even with fresh fuel and spark.
- Fuel smell or puddles under the carburetor from a stuck-open plunger.
- Intermittent starting after sitting overnight.
- A faint buzzing or clicking from the solenoid area when turning the key.
These issues often stem from coil burnout or debris jamming the valve, fixable with this drop-in replacement. Pro tip: While you're in there, inspect the fuel lines for cracks—old rubber hardens fast in the sun.
DIY Installation: Straightforward Steps for Any Boater
No shop required. Tools needed: Basic socket set, screwdriver, and multimeter for testing.
- Disconnect the battery and relieve fuel pressure by pinching lines or running dry.
- Unplug the wiring harness and remove the two mounting screws holding the old solenoid to the carburetor.
- Pull the solenoid straight out—note fuel line orientation.
- Install the new one, reconnect lines and wires (polarity doesn't matter on most), torque to spec (usually 2-3 ft-lbs), and test for leaks with a prime cycle.
Total time: Under 30 minutes. Fire it up on the water to verify smooth operation.
Maximize Longevity: Pro Maintenance Tips
Extend the life of your new solenoid and engine:
- Flush fuel system annually with stabilizer-treated gas.
- Store with fuel tank empty or stabilized to prevent gum-up.
- Check wiring for corrosion yearly—clean terminals with contact spray.
- Pair with a quality fuel filter upstream to catch debris before it reaches the solenoid.
Boat owners report fewer carb cleanings and better cold starts after upgrading, turning maintenance headaches into smooth sails.
Frequently Asked Questions
What engines is the Sierra 18-5879 solenoid compatible with?
It fits Yamaha 2-stroke 40hp (1984-1988), 50hp (1984-1988), 60hp (2001-2006), 70hp (1991-current), and 90hp (1984-1991) models. Verify your serial number for exact match.
How do I know if my Yamaha solenoid is bad?
Signs include no-start conditions, fuel leaks under the carb, buzzing noises on key turn, or hard starting after storage. Test with a multimeter for coil continuity.
Is this solenoid suitable for ethanol-blended fuels?
Yes, its corrosion-resistant materials handle E10 and similar blends better than older OEM parts, reducing internal buildup.
Can I install this solenoid myself?
Absolutely—it's a plug-and-play swap with basic tools. Disconnect power first, remove two screws, swap, and test. Takes about 20-30 minutes.
What's the difference between this Sierra solenoid and OEM Yamaha?
Sierra matches OEM specs using high-quality aftermarket materials for better durability in harsh marine conditions, often at a fraction of dealer costs.
Will this fix flooding issues on my outboard?
If the solenoid plunger is stuck open, yes—this provides a reliable shutoff. Check float valves too if flooding persists.
Does it require any special wiring?
No, it uses the stock two-wire harness. Ensure connections are clean and secure for optimal performance.
SKU: NVN-4003293
MPN: 18-5879
UPC: 808282292560
Technical specifications
| Brand | Sierra Engine Parts |
| Model | Sierra 18-5879 Yamaha 40-90Hp 2 Stroke Solenoid |
| SKU / MFR# | 4003293 |
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Frequently asked questions
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