Genuine Yamaha Thermostat
 
The Yamaha 6E5-12411-30 thermostat is primarily for older two-stroke Yamaha outboards, including models from 9.9 to hp through 250 hp, depending on the engine family and year. It is a different part from the 66M-12411-01 thermostat used on many Yamaha four-stroke outboards.
 
Compatible Yamaha models
Horsepower
Model examples
9.9–15 hp
9.9F, 9.9D, 15F, 15C, 15D
20–30 hp
20D, 25N (1994 onward), 30D
40–50 hp
40H, 40V, 40Y, 50, C50, P50
75–100 hp
75C, 90A, 100A
115–130 hp
115C, 130B, C115
150–200 hp
150F, 175D, 200F, 200G
225–250 hp
225D, 225G, 250A, 250B
V6 / HPDI variants
Z150P, Z150Q, Z175G, Z200N, Z200P
These are representative applications, not a guarantee that every year or suffix is compatible.
 
The thermostat is rated at 50°C (122°F), and catalogue references include superseded numbers 688-12411-10 and 688-12411-11.
 
Please get in touch to confrim if you are unsure