Bad feeling... (compression)

[_brad_]

Well, I think I have a bad feeling about my 1977 70 HP Evinrude.

Buying a compression tester tomorrow however today, I simply plugged the spark plug holes with my finger and turned the flywheel.

Top and middle cylinders seem to have compression and suction but when I tested the bottom cylinder I can hear a hissing noise coming from inside the middle and top spark plug holes and the flywheel simultaneously becomes easier to turn... Still compression and suction, but, I think it would definitely fail a leak down test...

 

[F_R]

Re: Bad feeling... (compression)

Pondering where there would be any connection between cylinders, all I can come up with is the exhaust area. So you must have a damaged cylinder on #3, blowing by into the exhaust. However, it doesn't seem like BOTH of the other ones would have open exhaust ports that you would be able to hear through.

In other words, I dunno. Now that you opened this question, let us know what you find.

 

[_brad_]

Re: Bad feeling... (compression)

Well, good news. Got a compression gauge today.

1.) #130
2.) #130
3.) #130

All good. Still not sure about the hissing noise but I guess the test speaks for itself.

Thanks!