Does anyone know what the compression is on a 1965 40hp evinrude big twin
F freddybell79 Cadet Joined Sep 3, 2014 Messages 10 Sep 15, 2014 #1 Does anyone know what the compression is on a 1965 40hp evinrude big twin
HighTrim Supreme Mariner Joined Jun 21, 2007 Messages 10,486 Sep 16, 2014 #2 Depends on your gauge. Also depends if you are using electric start or not. Roughly 90 to 125 psi.
