Yamaha - Pilot Jet #42.5 - Carburetor Fuel Metering Component - 7CU-E4142-42-A0

Overview

Pilot jets are one of the first things I look at when an engine won’t idle clean or feels off right off idle. It doesn’t take much—just a little buildup or the wrong size—and the whole low-speed range suffers. I’ve brought plenty of engines back to life just by swapping in the correct jet. When it’s right, the idle smooths out and throttle pickup feels crisp again.

Key Features

• Low-Speed Fuel Control – Regulates fuel flow at idle and low throttle for smooth operation.
• Precision Jet Sizing – Calibrated at 42.5 for accurate fuel-air mixture in carbureted systems.
• OEM Threaded Fit – Designed for proper installation and secure seating in the carburetor.
• Improved Idle Stability – Helps eliminate stalling, hesitation, and uneven low-speed performance.

Engine & Boat Compatibility

Designed for Yamaha outboard engines equipped with carbureted fuel systems that utilize a pilot jet for low-speed fuel control. Commonly used across a range of Yamaha outboards where smooth idle and clean throttle transition are essential.

FAQ

Q: What are signs this pilot jet is clogged?
A: Rough idle, stalling, or hesitation when you first throttle up are the most common signs.

Q: Can I clean the jet instead of replacing it?
A: You can try, but if performance doesn’t improve, replacement is usually the better option.

Q: Does using the wrong jet size affect performance?
A: Yes, it can throw off the fuel mixture and cause poor idle or sluggish response.

Q: How does fuel quality impact this part?
A: Dirty or old fuel can clog the jet quickly, especially without proper filtration.

Q: Is installation difficult?
A: It’s straightforward if you’re already working in the carburetor—just install it carefully and don’t over-tighten.