Volvo Penta 280, 280-DP, 285, 290, 290-DP, SP-A, SP-C, DP-A, DP-B, DP-C Sterndrive Workshop Manual (P/N 7731624-8)

• A 180-page English-language PDF of Volvo Penta’s workshop manual for 280, 285, and 290 series sterndrives and the Single Prop (SP) and Duoprop (DP) variants listed below.
• Upper gear housing repair and double bearing box service follow separate procedures for earlier and later drive designs.
• Lower gear overhaul covers propeller shafts, bearings, and seals, with separate single-prop and Duoprop procedures and housing-to-housing shimming.
• Intermediate housing reconditioning includes steering spindle, steering yoke, and retaining pawl service.
• Three shift mechanism configurations receive individual repair and adjustment instructions, including a serial-number break between the first two designs.
• Pressure and vacuum testing, trim-cylinder replacement, and power trim wiring diagrams support sealing checks and trim-system repair.

Written primarily for Volvo Penta service workshops and their qualified personnel, this manual assumes basic knowledge of marine drive systems and the ability to perform mechanical and electrical work.

Model Coverage and Production Changes

The standard versions covered are 280, 280T, 280PT, 285, 285A, 290, and 290A. Earlier Duoprop coverage includes 280-DP, 280-DP/PT, 290-DP, and 290A-DP.

Later models are SP-A, SP-A1, SP-A2, and SP-C, plus DP-A, DP-A1, DP-A2, DP-B, DP-B1, DP-C, and DP-C1. Generation charts identify changes in sliding sleeves, bearings, and housings, including the DP-C1 propeller shaft and cone.

For the 280/285/290-family shift mechanisms, Type 1 applies through PZ 2829528; Type 2 begins at PZ 2829529. Type 3 and SP/DP assembly procedures are addressed separately.

Component Overhaul and Mechanical Specifications

The upper gear sections distinguish 280/285/290 construction from 290A/SP/DP designs, including integrated-bearing and crush-sleeve arrangements. The text explains how to calculate required shim thickness using stamped factory markings and fixed nominal dimensions, with alternative trial-shim methods followed by gear backlash and contact-pattern checks.

Duoprop procedures address the inner and outer propeller shafts, forward gear, and intermediate bearing. Shaft runout and bearing preload checks accompany the assembly instructions. Universal joint maintenance includes spider and needle-bearing inspection.

The manual warns that an unsuitable puller used on the Duoprop outer-shaft bearing race can score the shaft’s sealing surface and allow water into the drive.

Reinstallation coverage addresses universal-joint and exhaust bellows, shift-cable adjustment, and retaining-pawl checks. Propeller sections distinguish long- and short-hub hardware and A/B Duoprop sets. Separate procedures cover SP rotation changes, trim-fin adjustment, and twin-drive toe-out.

Trim, Steering, and Electrical Coverage

Trim-system repair includes electromechanical tilt fault checks, pump-motor and reservoir service, filter replacement, hydraulic bleeding, and operational testing. Sender, gear-rack, and gear-wheel replacement procedures include trim-instrument adjustment for transom angle and SP/DP configuration.

The pump adapter and relief-valve assemblies are replaced as units; their factory settings are not intended for internal adjustment. Lubrication notes warn that mixing ATF and engine oil in the trim system can cause foaming and pump failure.

The steering helmet and fork are also replaced as an assembly. Power-steering cylinder overhaul requires separate instructions, publication 7734865-4, referenced by this manual.

Section views of the 280 and DP drives accompany wiring diagrams for the 280 tilting device, 280 power trim, early 290 power trim, and later 290/SP/DP power trim. The tilting-device diagrams include a USA version; wiring references identify components and cable colors.

Technical Data Preview

Model-specific tables provide gear ratios, lubricant specifications, fluid capacities, fastener torques, backlash, and preload data. The special-tool catalog identifies applications and part numbers, including pressure tester 3810152-3, vacuum tester 3858578-2, and shift-mechanism holding plate 3856761-6.

The manual also covers 1-inch and 4-inch sterndrive extensions, allowable housing welding repairs, and paintwork for corrosion protection. Its repair scope is the sterndrive and related systems; engine overhaul is outside this volume.

Always adhere to factory torque specifications and safety protocols when handling heavy marine drivetrain components, including securely supporting a raised sterndrive.