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.
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.
135 to 160 most important thing is that they are all less than 5 psi difference
The dry weight of the 1985 model, 70 hp Evinrude outboard is 257 lbs.
19 degrees BTDC, + or - 1 degree at WOT. Around 4 degrees ATDC idle timing.
It should be at least 70 psi
It should have a minimum of 70 psi.
It is a 70 HP 1975 Evinrude. The 5 indicates the year. I just bought a1975 Evinrude yesterday & looked up the number.
19 degrees
A 70 hp Evinrude outboard, model number E70ELCO, would be a 1985 year model.
1992
The 1977 model, 70 hp Evinrude outboard requires an NGK BZ7HS-10, or a Champion QL77JC4 Plug gapped to .030 in.
The compression gauge reading should be no less than 100 psi. Check all 4 cylinders and note the readings. The lowest should not be less than 70% of the highest reading.