Mercury MerCruiser Trim Cylinder Spacer 840802

Mercury MerCruiser Trim Cylinder Spacer — 840802

What This Part Does

The 840802 is a genuine Mercury OEM trim cylinder mounting spacer used in selected MerCruiser Bravo-series sterndrive integrated transom and gimbal ring assemblies. It installs at the trim cylinder mounting pin positions and maintains the correct spacing and alignment of the trim cylinder attachment points. Two 840802 spacers are shown per assembly — one at each trim cylinder mounting position. The spacer works together with the mounting pins and retaining rings to secure the trim cylinders and allow correct pivoting through the trim range.

Compatible Applications

• MerCruiser Bravo sterndrive integrated transom assemblies where the parts diagram specifies 840802
• MerCruiser Bravo X / XZ configurations using the applicable power-trim cylinder arrangement

Confirm by MerCruiser drive model, transom assembly configuration, and serial number. The exact assembly serial number determines which spacers and mounting hardware apply to the specific installation.

Serial Number & Fitment Notice

Confirm the drive model and transom assembly serial number against the applicable Mercury gimbal ring / integrated transom schematic before ordering. The same assembly also contains a separate 840803 spacer at a different diagram position — 840802 and 840803 are not interchangeable. Always match by diagram position and part number:

• 840802 — spacer, quantity 2 (this part)
• 840803 — separate spacer, typically quantity 1 (different position)
• 805272 — retaining ring, quantity 2

Dimensions

Exact dimensions are not published in the Mercury consumer catalog. Confirm fitment via the gimbal ring / integrated transom parts diagram for your specific drive model and serial number. Do not substitute 840803 based on visual similarity — the two spacers differ in geometry at the mounting-pin contact surface.

When to Replace

• Visible wear, grooving, or elongation at the mounting pin contact surface
• Corrosion or pitting on the spacer body
• Distortion from impact or excessive trim cylinder movement
• Excessive looseness at the trim cylinder mounting point
• Damage found during trim cylinder removal or transom service

Wear in the spacers should also prompt inspection of the mounting pins, retaining rings, and adjacent bushings. Replace in pairs — both port and starboard — whenever one shows wear.

Service Interval

Inspect the trim cylinder mounting spacers during any transom, gimbal ring, or trim cylinder service. No fixed replacement interval applies, but replacement is recommended whenever the assembly is disassembled and the spacers show wear, corrosion, or looseness. Inspect both spacers together — if one is worn, the other typically needs replacement as well.

Installation Notes

• Inspect both 840802 spacers — replace as a pair if either shows wear
• Check mounting pins for scoring, corrosion, or deformation before reinstalling
• Inspect retaining rings (805272) for deformation — replace if compressed or distorted
• Inspect adjacent bushings for excessive play
• Confirm trim cylinders pivot freely through the full trim range after assembly
• Follow the Mercury service procedure for the specific transom assembly and serial number
• Do not force a worn or corroded spacer onto the mounting pin — damage to the pin or surrounding hardware can affect trim cylinder alignment and operation

Alternate & Superseded Part Numbers

• 840802 — Mercury / MerCruiser OEM number
• 23-840802 — Mercury catalog prefix format

No superseding number is confirmed. 840802 remains listed as an active Mercury part. Do not substitute 840803 — it is a different spacer at a different diagram position in the same assembly.

Related Parts

• 840803 — separate trim cylinder spacer (different diagram position, qty 1)
• 805272 — retaining ring (qty 2 per assembly)
• 840728 — trim cylinder mounting pin
• 8M0108286 — starboard trim cylinder assembly
• 8M0108285 — port trim cylinder assembly
• 806189T1 — trim cylinder anode assembly

Technical FAQ

Q: Do I need to order two of these?
A: Yes — the Mercury parts diagram shows two 840802 spacers per assembly, one at each trim cylinder mounting position (port and starboard). This listing is sold individually, so order 2 for a complete assembly service.

Q: Is 840802 the same as 840803?
A: No. Both are spacers used in the same trim cylinder mounting assembly, but they are different parts at different diagram positions. 840802 is used at quantity 2; 840803 is a separate spacer typically shown at quantity 1. Match by diagram position and part number — not by appearance.

Q: Should I replace the retaining rings and mounting pins at the same time?
A: Yes, as a best practice. While the trim cylinder assembly is apart, inspect the retaining rings (805272) and mounting pins (840728) for wear, corrosion, or deformation. Replacing worn hardware together prevents having to disassemble the assembly again shortly after.

Q: How do I confirm this is the right spacer for my Bravo drive?
A: Locate the gimbal ring / integrated transom schematic for your specific MerCruiser drive model and transom assembly serial number, and confirm that 840802 appears at the trim cylinder mounting spacer position (ref #24 where applicable). If the spacer being replaced still has a visible part number, that is the fastest confirmation.

Q: Can trim cylinder misalignment be caused by a worn spacer?
A: Yes. Worn or elongated spacers allow excess movement at the trim cylinder mounting point, which can affect trim cylinder alignment, pivot geometry, and in severe cases contribute to uneven trim operation. Replace worn spacers before reassembling the trim cylinder hardware.

Parts Desk Insights

The most common issue with 840802 is customers confusing it with 840803 — both are spacers in the same assembly and they look similar, but they are different parts at different positions. Always confirm by diagram position, not appearance. The other frequent situation is customers ordering just one when the assembly requires two — this is a sold-individually part and the diagram calls for a pair. If a customer is pulling the trim cylinders for any reason, recommending the retaining rings (805272) and a check of the mounting pins (840728) at the same time is good practice, since those parts are hard to access without the cylinders already removed.