Crankshaft Upper Main Bearing – Fits Yamaha 75-90HP 2-Stroke Outboards (Replaces 93310-636U4-00)

Product Details

This is a high-quality aftermarket Crankshaft Upper Main Bearing – Fits Yamaha 75-90HP 2-Stroke Outboards, designed for a range of models including 75HP (1994–up), 85HP (1992–1993), and 90HP (1984–2006). It serves as a crucial internal component, ensuring smooth crankshaft rotation at the top of the assembly.

This part is a direct replacement for Yamaha OEM part 93310-636U4-00 and serves as an interchange for OVERSEE 93310-636U4, ITACO 93310-636U4-00, and SAIL MARINE 93310-636U4.

• Installs as the top bearing on the engine crankshaft.
• Engineered for the demanding internal environment of marine engines.
• Constructed from durable Metal/Metallochrome for long service life.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This bearing is confirmed to fit the extensive list of Yamaha 2-stroke models detailed here. While some sources suggest compatibility with Parsun 75, 85, and 90 HP outboards, specific model numbers are not confirmed, so purchase based on Yamaha cross-reference only.

Technical Specs

Product Type

Crankshaft Upper Main Bearing

Installation

Internal engine component

Housing Material

Metal/Metallochrome

Housing Color

Silver

Product Dimensions

7.5 × 9.0 × 5.0

Weight

26g (0.026 kg)

Warranty

1 year (OVERSEE brand)

Other Technical Attributes

Top crankshaft bearing

What’s in the Box

• 1 x Crankshaft Upper Main Bearing (Replaces 93310-636U4-00)

Installation Notes

1. Disconnect the battery and all electrical connections to the engine to prevent accidental starts.
2. Drain the engine oil and coolant completely according to your service manual.
3. Carefully disassemble the engine powerhead to access the crankshaft assembly. This requires specialized tools.
4. Remove the old upper main bearing. Inspect the crankshaft journal for any scoring or damage.
5. Thoroughly clean the bearing seat and surrounding area of any old oil, debris, or contaminants.
6. Lubricate the new bearing and the crankshaft journal with fresh, clean engine oil before installation.
7. Carefully press the new bearing into place, ensuring it is properly seated and aligned without damage.
8. Reassemble the engine, torquing all bolts to the manufacturer's specified values and sequence.
9. Refill the engine with new oil and coolant.
10. After reassembly, check thoroughly for any leaks before starting the engine. Test run at low RPMs initially.

Due to the complexity of this procedure, professional installation by a qualified marine mechanic is strongly recommended for safety and to ensure proper performance.

Troubleshooting & FAQ

Safety & Important Info

• Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
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