Thermostat question -- 140 or 160 degrees?

[jbutler67]

1998 Mercruiser 5.7 Alpha with Closed Cooling and Carburetor
M048938

Thermostat question -- 140 or 160 degrees?

 

[Rick Stephens]

I'd be running at least a 160, which is what the OEM part number 991551 is..