Mercury MerCruiser Power Steering Pump Pulley – 8M0150723

Mercury MerCruiser Power Steering Pump Pulley – 8M0150723

Part Number: 8M0150723
Brand: Mercury Marine / Quicksilver
Official Product Type: Power Steering Pump Pulley – OEM
System: Accessory Belt Drive / Power Steering
Drive Type: Serpentine belt
Diameter: Approx. 5-3/4 in (146 mm)
Material: Marine-grade steel

About This Part

This is the genuine Mercury OEM power steering pump pulley for MerCruiser sterndrive engines equipped with a serpentine belt accessory drive system. The pulley mounts directly to the power steering pump shaft and is driven by the serpentine belt, transferring rotational power from the crankshaft to maintain hydraulic pressure for smooth, responsive steering. A worn, cracked, or misaligned pulley causes belt squeal, belt misalignment, accelerated belt wear, and in severe cases, loss of power steering assist.

Compatible Applications

• MerCruiser 4.3L V6 – serpentine belt accessory drive models, approx. 1996–2014
• MerCruiser 5.0L V8 – serpentine belt accessory drive models, approx. 1996–2014
• MerCruiser 5.7L V8 – serpentine belt accessory drive models, approx. 1996–2014
• MerCruiser 6.2L V8 – serpentine belt accessory drive models, approx. 1996–2014
• MerCruiser 7.4L V8 – serpentine belt accessory drive models, approx. 1996–2014
• MerCruiser 8.2L V8 – serpentine belt accessory drive models, approx. 1996–2014

Always verify fitment using your engine serial number. MerCruiser engines of the same displacement can use different accessory drive layouts depending on model year, cooling configuration, and production serial range. Confirm part number 8M0150723 appears on the Mercury MerCruiser parts diagram for your engine before ordering.

Serial Number / Fitment Note

Locate your MerCruiser engine serial number on the engine block tag or flame arrestor decal. Cross-reference against the Mercury MerCruiser parts diagram for your engine model to confirm this is the correct pulley for your power steering pump configuration. Some MerCruiser engines use a V-belt accessory drive rather than a serpentine belt — this pulley is for serpentine belt systems only.

System & Diagram Position

This pulley is found in the Accessory Belt Drive / Power Steering section of the Mercury MerCruiser parts diagram. It mounts on the power steering pump shaft and interfaces with the serpentine belt to drive the pump. Adjacent components in the same diagram section include the serpentine belt, seawater pump pulley, tensioner pulley, idler pulley, and power steering pump body.

Supersedes / Cross-Reference Numbers

• 861578 – earlier Mercury MerCruiser part number for this pulley
• 807731T – cross-reference number
• Sierra 18-8297 – aftermarket equivalent (OEM recommended for best fit and longevity)

When to Replace

• Visible cracks, chips, or damage to the pulley face or hub
• Grooves worn smooth — a worn groove causes the belt to slip and squeal
• Pulley wobble or runout when spun by hand (indicates a bent hub or worn pump shaft bearing)
• Belt misalignment traced to the power steering pulley position
• Replacing the power steering pump — inspect the pulley at the same time and replace if worn

Installation Notes

• A pulley puller and installer tool is typically required — do not hammer the pulley onto the pump shaft as this will damage the pump bearing
• Confirm pulley alignment with adjacent pulleys using a straightedge before reinstalling the serpentine belt
• Inspect the serpentine belt for wear and replace if it has been running on a damaged pulley
• Torque the pump shaft nut to the specification in the Mercury MerCruiser service manual
• Check power steering fluid level after installation and bleed the system if required

Related Parts

• Mercury MerCruiser Power Steering Pump without Pulley – 16792A39
• Mercury MerCruiser Power Steering Hose – 8M0063020
• Mercury MerCruiser Seawater Pump Pulley – 8M0150724
• Mercury MerCruiser Serpentine Belt Pulley Kit – 8M0150824
• Quicksilver Water Pump Pulley – 8M0153706
• Mercury MerCruiser Quicksilver Tensioner Pulley – 865777
• Mercury MerCruiser Quicksilver Serpentine Belt – 865615Q03
• Mercury Quicksilver Power Trim and Steering Fluid – 858074K01

Technical FAQ

Do I need a special tool to remove and install this pulley?
Yes. A pulley puller is required to remove the old pulley from the pump shaft without damaging the pump. A pulley press or installer tool is required to seat the new pulley to the correct depth. Hammering the pulley on will damage the pump shaft bearing and void any warranty on the new pump.

How do I know if the pulley or the pump is the problem?
Spin the pulley by hand with the belt removed. If it wobbles, has rough spots, or feels loose on the shaft, the pulley is the issue. If the pulley spins smoothly but the pump is noisy or leaking, the pump itself needs attention. In many cases both are replaced together.

Can I use an aftermarket pulley?
Aftermarket pulleys are available, but pulley diameter and groove profile must match exactly — even a small difference affects belt tension and alignment across the entire accessory drive. OEM is the safest choice to maintain correct belt geometry.

What causes power steering pulleys to fail on marine engines?
The marine environment accelerates corrosion on the pulley hub and shaft interface. Saltwater exposure, bilge moisture, and infrequent use (which allows corrosion to set in) are the primary causes. Inspect the pulley annually as part of routine belt service.

Parts Desk Insights

Best use case: This pulley is the right call when a MerCruiser sterndrive is showing belt squeal, belt misalignment, or heavy steering that traces back to the power steering side of the accessory drive. It’s also the correct part to order alongside a power steering pump replacement — if the pump has failed, the pulley has almost certainly been running under stress and should be inspected and replaced at the same time.

Common mistakes: The most frequent error is attempting to remove or install the pulley without the correct puller and installer tools — this damages the pump shaft bearing and turns a straightforward pulley swap into a pump replacement. Also watch for customers ordering this pulley for a V-belt drive MerCruiser — confirm the engine uses a serpentine belt system before ordering. A second common mistake is replacing the pulley without replacing the serpentine belt at the same time; if the pulley was damaged, the belt has been running on a bad surface and should be replaced as a set.