This Mercury Power head rebuild Kit will fit all 40 Hp 1990-1997, 45 Hp 1986-1989, 50 Hp 1970-1985 4 Cylinder 2.565" Bore. Kits comes complete with all parts needed to rebuilt your Engine.
Please Note: STD. bore is a direct fit and does not need boring, a light hone to break the glaze is fine for seating the new rings. However, if there is damage or excessive wear to your cylinder, then your cylinder will need to be bored over, then you will need to purchase the correct oversize that will remove all scoring in the sleeve. Refer to you service manual for more information.

Piston OEM# 743-5172A, 743-5172A6, 780-9229A

Kit includes:

4 Pistons 100-05K OEM# 743-5172A
4 200-05 Rings (200-05) Japanese RIK Performance TOP industry quality Pistons & Ring sets.
4 Pins (300-05)
8 Clips (400-04) OEM# 40-828119
1 Complete Gasket Kit (500-200) OEM# 27-72486A32
1 Upper Main Bearing (010-221-01) OEM# 30-63742
2 Center Main Bearing Needles Only Set (010-132-56) OEM# 29-20046
1 Lower Main Bearing (010-221-01) OEM# 30-63742
4 Top End Needle Bearings (010-126-27) OEM# 29-20063
4 Lower Rod bearings (010-135-25) OEM# 29-20046
8 Rod bolts (805-200) OEM# 10-91012

Please be advised that Mercury Re-Build Kits DO NOT go by the year they were produced. So please check all information available such as the following to identify your engine to the correct part.

1. OEM#'s next to each part in kit if available in our listing.
2. Piston bore size


At PwcEngine,com we offer top name brands including WSM, Pro-X, Wiseco pistons, OEM RIK Japan rings, Nachi, Koyo, & KBC Engine bearings. PWC Engine use the highest quality gaskets and seals in the industry.

• High Performace Quality OEM Style Re-build Kits.
• Re-build Kits meet OEM standards or higher.
• PWC Engine brings Higher Quality for an awesome price!

High Performace Quality OEM Style Re-build Kits.Water Sport Manufacturing