This WSM powerhead rebuild kit is for Mercury and Mariner 100 and 115 HP L4 4-cylinder powerheads using the bottom-guided rod configuration. The 3.375-inch bore and bottom-guided design are important fitment details because a separate top-guided kit is used on the later version of this engine family.
Fitment
- Mercury/Mariner 100 HP L4 4-cylinder: 1989-1993
- Mercury/Mariner 115 HP L4 4-cylinder: 1989-1993
Technical Specifications
- WSM standard-size kit: 100-25-20
- 4-cylinder L4 looper powerhead
- 3.375-inch standard bore
- Bottom-guided connecting-rod configuration
- WSM catalogs distinguish this 100-25-20 family from the later 100-35-20 top-guided kit
Piston Size Options
- Standard
- .010 oversize
- .015 oversize
- .020 oversize
- .030 oversize
- .040 oversize
Measure the finished cylinder bore before selecting piston size.
Complete Kit Includes
- 4 WSM piston kits with rings, wrist pins, and clips
- Complete gasket kit: 1 head-cover gasket, 1 base gasket, 8 carburetor gaskets, 8 reed-block gaskets, 2 intake gaskets, 2 exhaust gaskets, 1 lower end-cap O-ring, 1 lower crank O-ring, 1 3.0L O-ring, 1 fuel-pump gasket, 1 thermostat gasket, 1 upper oil seal, and 1 lower end-cap oil seal
- 1 upper main bearing, 3 center main bearings, and 1 lower main bearing
- 4 upper and 4 lower connecting-rod bearings
- 8 connecting-rod bolts
Fitment Note
Mercury and Mariner V6 and L4 applications can differ by bore, rod-guidance style, induction system, cylinder-head sealing style, connecting-rod family, and serial range. Verify the technical details above against the engine before ordering.
Questions About This Product?
Have questions about this product? Email us at customerservice@marinepartswarehouse.com and include your motor information with your question.
