135 to 160 most important thing is that they are all less than 5 psi difference
Compression on a 1975 70 hp Evinrude outboard refers to the pressure generated within the engine's cylinders during the compression stroke, which is crucial for efficient combustion. Typically, compression readings for this model should be between 90 to 120 psi. Low compression can indicate issues such as worn piston rings, damaged cylinder walls, or valve problems, which can affect engine performance and reliability. Regular compression testing is essential for maintaining the health of the outboard motor.
The dry weight of the 1985 model, 70 hp Evinrude outboard is 257 lbs.
19 degrees
The 1977 model, 70 hp Evinrude outboard requires an NGK BZ7HS-10, or a Champion QL77JC4 Plug gapped to .030 in.
A 70 hp Evinrude outboard, model number E70ELCO, would be a 1985 year model.
The compression for a 1984 70 hp Evinrude outboard motor should typically be between 100 and 130 psi per cylinder. It's important that the compression is relatively consistent across all cylinders, with no more than a 10% variance between them. If the compression is significantly lower than this range, it may indicate issues such as worn rings, damaged pistons, or other mechanical problems. Always refer to the specific service manual for your model for the most accurate specifications.
50:to1
The dry weight of an 1986 model, 70hp Johnson outboard, with tilt and trim, is 256 lbs.
The 1981 model, 70 hp Evinrude, requires a 50:1 ratio, one pint of 2 cycle oil, to six gallons of fuel.
19 degrees BTDC, + or - 1 degree at WOT. Around 4 degrees ATDC idle timing.
i have a 70hp mercury outboard older late 70's model and the cylinder compression is 135 across the board. it shouldnt be below 100 psi and not more that 15 between any 2 cylinders
The torque specification for the cylinder head on a 1986 Evinrude 70 hp motor is typically around 25 to 30 foot-pounds (ft-lbs). It's crucial to follow a specific torque sequence for even pressure distribution. Always refer to the service manual for the exact specifications and procedures to ensure proper installation.