21827365 Shaft Coupling | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta two-piece rigid propeller shaft coupling for a 25 mm shaft, 63 mm long with a 102 mm flange diameter and weighing 3.225 kg. The two-piece conic design centres itself on the shaft, so no tapering or keyway cutting is needed - the shaft is simply cut to length and the coupling cone fitted, then secured to the coupling flange with the bolts provided. The catalogue gives the material as high grade 1018 steel to ISO E 235 with a zinc-nickel coating and sealer, and the required shaft tolerance as h9, plus 0.0 to minus 0.052. It is delivered complete with bolts, nuts, washers and installation instructions.

⚙️ Key Features

• For a 25 mm propeller shaft
• 63 mm long, 102 mm flange diameter
• Two-piece self-centring conic design, no shaft machining required
• High grade 1018 steel to ISO E 235, zinc-nickel coated and sealed
• Shaft must be to h9 tolerance, plus 0.0 to minus 0.052
• Supplied with bolts, nuts, washers and instructions
• Simplified installation and alignment
• Less vibration and noise
• No machining required
• Two-piece conic design
• Perfect central alignment
• High torsional hold without shaft damage
• Compact dimensions, low weight
• Virtually maintenance free
• Easy to disconnect the propeller shaft, without re-adjustment
• Integrated counterhold
• Better onboard comfort
• Flange diameter d: 102 mm (4.02 in)
• Length l: 63 mm (2.48 in)
• Material: high grade 1018 steel (ISO E 235) with zinc-nickel coating and sealer
• Required shaft tolerance: h9 (+0.0 -0.052)
• Shaft diameter: 25 mm
• Weight: 3.1 kg (6.8 lb)
• Fits: D1 with MS10 or MS15 gearbox

📋 Kit Contents

• 1 × two-piece conical 25 mm shaft coupling assembly - 21827365
• Coupling bolts - supplied within assembly 21827365; no separate component number published
• Coupling nuts - supplied within assembly 21827365; no separate component number published
• Coupling washers - supplied within assembly 21827365; no separate component number published
• Installation instructions - supplied with assembly 21827365

🔌 Function

Clamps the 25 mm propeller shaft concentrically to the gearbox output flange, carrying drive torque and propeller thrust between them.

⚠️ Common Signs of Failure

• Vibration through the hull that follows shaft speed
• Coupling creeping along the shaft or running out of true
• Corrosion or fretting at the shaft interface
• Rust weeping from the clamped joint
• Clamping faces scored or picked up on removal

🛠️ Service Notes

• Shaft diameter is the deciding dimension - this is the 25 mm coupling and 21827366 is the 30 mm one, and only 17 grams separate them, so weight is no guide
• The shaft must be to h9 tolerance and true at the clamping area or the coupling cannot grip properly
• Realign the shaft to the gearbox after the coupling is fitted
• Required shaft tolerance is h9 (+0.0 -0.052)
• Cut the shaft to length and fit the cone - no tapering or keyway cutting is needed

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21827365 → Supersedes 827924 → Supersedes 827925

OEM / Related Numbers

• 827924 earlier number superseded by this part
• 833838 earlier number superseded by this part
• 827925 earlier number superseded by this part

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging