I did a compression test and got 119 on all 3 cylinders. Is this good and what is the compression on a new Evinrude 75. I did the test with spark plugs in and wires off except for the cylinder being tested. (obviously) Also is it possiable for the compresson to go down after a decarb of the motor?
<br /><br />119-119-119 is an excellent set of readings, even with two plugs in. Excellent because all three are equal. That is what is important.<br /><br />The actual readings depend on a lot of factors, including guage, technique, engine temp and battery condition, so anything over about 100lb is good.<br /><br />It is theoretically possible for compression readings to go down after a decarb, but VERY unlikely unless the engine is toast or the decarb was badly done.