Sureshot
Petty Officer 3rd Class
- Joined
- Sep 28, 2011
- Messages
- 97
Hello folks. I have a 2000 Johnson 50 HP 2-stroke outboard that is suffering from low compression on one of the cylinders. I did a cold compression test and got a reading of 120 PSI on the top cylinder and just 30 PSI on the lower one. I read some instructions about trying a "wet" compression test so I sprayed the lower cylinder with some fogging oil and re-tried the test. PSI rose up to around 45-50 PSI. Is that a good sign?
Seems like compression this low would mean major trouble but since the PSI raised after the "wet" test, maybe I should give decarbing a shot? The spark plug that came off the bad cylinder seems to have a sooty gray covering over it. I am a rookie when it comes to outboard motors so I'm looking for some much appreciated guidance. Thank you.
Seems like compression this low would mean major trouble but since the PSI raised after the "wet" test, maybe I should give decarbing a shot? The spark plug that came off the bad cylinder seems to have a sooty gray covering over it. I am a rookie when it comes to outboard motors so I'm looking for some much appreciated guidance. Thank you.