87-805605A1 Oil Pressure Sender Sensor Switch for Mercruiser | JLM Marine

Oil Pressure Sender Sensor Switch 87-805605A1 – Fits MerCruiser 4.3L, 5.0L, 5.7L Engines

This oil pressure sender sensor switch is designed to fit MerCruiser marine engines, specifically models equipped with 4.3L, 5.0L, and 5.7L powerplants. It monitors low oil pressure conditions and triggers the alarm system to protect your engine from damage. Engineered as a direct aftermarket replacement for OEM part number 87-805605A1, this sensor ensures reliable performance and engine safety.

This switch directly replaces MerCruiser part #87-805605A1, Sierra part #OP22900, Crusader part #97767, and Marine Power part #457045, providing broad cross-brand compatibility for your marine engine needs.

• Senses low oil pressure (6 PSI) and shuts off electric fuel pump to prevent engine damage
• Terminal type: 10-32 stud; Thread size: 1/8-27
• Aftermarket replacement offering reliable performance at competitive pricing

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 × Oil Pressure Sender Sensor Switch

Installation Guide

1. Disconnect the battery's negative terminal to prevent electrical shorts during installation.
2. Locate the existing oil pressure sender on your MerCruiser engine block or oil filter housing.
3. Disconnect the electrical connector from the old sender by carefully pulling it away from the terminal stud.
4. Using an appropriate wrench, unscrew the old oil pressure sender counterclockwise from the engine block.
5. Clean the threaded mounting hole to remove any debris, old sealant, or metal particles.
6. Apply a small amount of thread sealant (Teflon tape or pipe sealant) to the threads of the new sender.
7. Hand-thread the new oil pressure sender clockwise into the mounting hole until snug.
8. Tighten the sender with a wrench to the manufacturer's recommended torque specification (typically 10–15 ft-lbs)—do not overtighten.
9. Reconnect the electrical connector to the 10-32 stud terminal on the new sender.
10. Reconnect the battery's negative terminal.
11. Start the engine and check for oil leaks around the sender; verify that the oil pressure alarm system functions correctly.
12. If the alarm does not activate under low-pressure conditions or leaks persist, re-check installation and connections.

Troubleshooting & FAQ

Q: How do I confirm this oil pressure sender fits my MerCruiser engine?
A: Verify that your engine is a 4.3L, 5.0L, or 5.7L MerCruiser model and that your original sender matches part number 87-805605A1, OP22900, 97767, or 457045. Cross-reference the terminal type (10-32 stud) and thread size (1/8-27) with your existing sender.

Q: What are the signs that my oil pressure sender needs replacement?
A: Common symptoms include a constantly illuminated or flickering oil pressure warning light, failure of the alarm to activate during low oil pressure, erratic gauge readings, or visible oil leaks around the sender body.

Q: How often should I replace the oil pressure sender?
A: Oil pressure senders typically last several years under normal conditions. Replace immediately if you notice warning light malfunctions, erratic readings, or oil leaks. Regular engine maintenance inspections can help identify issues early.

Q: Will this aftermarket sender shut off the fuel pump like the OEM part?
A: Yes, this aftermarket sender is designed to sense low oil pressure at 6 PSI and trigger the shutoff signal to the electric fuel pump, just like the original OEM component.

Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.