Thermostat Diaphragm - Johnson / Evinrude 120-300 HP Looper (1987-1988, 1990-1993) OEM# 0394408 | WSM 540-05

Thermostat Diaphragm Johnson / Evinrude 120 - 300 Hp Looper 85-93 OEM# 0394408

This WSM thermostat diaphragm is a quality aftermarket replacement part designed for Johnson/Evinrude 4 Cyl 3.500 Small Bore Looper 140 and 13 other compatible models.

It replaces selected OEM reference numbers including 0394408, 777842, 878746, G46130, S18-1222 and is suitable for service, repair and rebuild work.

Key Features

• Quality aftermarket replacement part from WSM
• Engineered for dependable fit, function and service life
• Designed for marine and powersports repair and maintenance
• Compatible with 15 listed fitments
• Replaces selected OEM reference numbers listed below

Product Details

• Brand: WSM
• WSM Part Number: 540-05
• Product: Thermostat Diaphragm
• OEM Reference: 0394408, 777842, 878746, G46130, S18-1222
• Application: Johnson/Evinrude 4 Cyl 3.500 Small Bore Looper 140 and 13 other compatible models

Product Fitment

This part is suitable for the following models:

• Johnson/Evinrude 4 Cyl 3.500 Small Bore Looper 140 – 1985-1987
• Johnson/Evinrude 4 Cyl 3.685 Big Bore Looper 120 – 1985-1987
• Johnson/Evinrude 4 Cyl 3.685 Big Bore Looper 125 – 1988-1991
• Johnson/Evinrude 4 Cyl 3.685 Big Bore Looper 140 – 1989-1990
• Johnson/Evinrude 6 Cyl 3.500 Bore Cross Flow 185 – 1988-1991
• Johnson/Evinrude 6 Cyl 3.500 Small Bore Looper 200 – 1990-1992
• Johnson/Evinrude 6 Cyl 3.500 Small Bore Looper 225 – 1986-1987
• Johnson/Evinrude 6 Cyl 3.685 Big Bore Looper 200 – 1986-1987
• Johnson/Evinrude 6 Cyl 3.685 Big Bore Looper 225 – 1988-1992
• Johnson/Evinrude Johnson/Evinrude – 1988-1992
• Johnson/Evinrude 8 Cyl 3.500 Small Bore Looper 300 – 1985-1987
• Johnson/Evinrude 8 Cyl 3.685 Big Bore Looper 250 – 1985-1987
• Johnson/Evinrude 8 Cyl 3.685 Big Bore Looper 275 – 1991-1993
• 8 Cyl 3.685 Big Bore Looper 300 – 1988
• 1988-1993

Why Buy WSM

WSM is a trusted manufacturer of aftermarket marine and powersports parts, known for dependable quality, strong fitment coverage and workshop-ready replacement components.

You May Also Need

Browse related parts for compatible models:

• Ignition Coil Johnson / Evinrude 2 - 300 Hp 85-06 OEM# 0582508 – 375-2508-09
• O-Ring Crankshaft Johnson / Evinrude 88 - 300 Hp 86-01 OEM# 0332585 – 525-05
• O-Ring Crankshaft Johnson / Evinrude 88 - 300 Hp 86-01 OEM# 0332585 – 525-05-01
• Piston Clips Johnson / Evinrude 120 - 300 Hp OEM# 0326765 – 400-24

Please use the fitment guide, OEM references and images to confirm this is the correct part before ordering.