Drewski Canuck
Active Member
Had the last Demons cast out of my rebuilt Johnson 120. It's a 92, but Compression on the rebuild was 130 - 135 so a good rebuild. Problems with idle and hard start were finally found in that one carb was rejetted improperly meaning one side would not idle, and a thermostat was leaking so no Heat on one side resulting in improper combustion temperatures.
Outfit did a Dyno test and got it to 2300 PSI which is Spec. They also did a Vacuum / Leak Down test. Results were 8 - 10 % across the cylinders. I have never seen this done before. Maybe its the ****** shops I went to in the past, none of them had a Dyno unit.
Can anyone tell me what does a vacuum / leak down test show, and what is the expected "percentage" for an outboard 2 stroke? I understand that all rings are split, and all pistons will leak eventually due to the split rings installed. So why did they do this, and does it mean anything?
Drewski
Outfit did a Dyno test and got it to 2300 PSI which is Spec. They also did a Vacuum / Leak Down test. Results were 8 - 10 % across the cylinders. I have never seen this done before. Maybe its the ****** shops I went to in the past, none of them had a Dyno unit.
Can anyone tell me what does a vacuum / leak down test show, and what is the expected "percentage" for an outboard 2 stroke? I understand that all rings are split, and all pistons will leak eventually due to the split rings installed. So why did they do this, and does it mean anything?
Drewski
