Johnson 88, one spark plug different

[surrender]

last year had a problem with starboard lower plug having salt like deposits on it. traced to probable bad gasket on exhaust water gasket or head gasket. Fixed and all seemed well. Now that same plug seems to maybe have a lean condition. The plug is dryer then the others as far as oil on it with tannish brown deposits. From a plug inspection stand point, if this was a four stroke i think the plug looks good,...but being a two stroke and since the other three plugs show a little oil deposits on them is my dryer plug a sign of that cylinder running lean? If so i guess that will cause a problem if it is not fixed. i suppose a thorough carb cleaning is in order. Any thoughts?

[oldcatamount]

I'd try cleaning and re-gapping all the plugs first, then test the results. Are the plugs all the same number?

[DargelJohn]

The cylinder that is running lean, check the bypass cover for leaks.

[surrender]

All the plugs are the same, Champion Q's, I will check the bypass cover. How would one go about that?

[DargelJohn]

All the plugs are the same, Champion Q's, I will check the bypass cover. How would one go about that?

Attached pic shows the bypass covers. Check for oil leaks around edges. If the cover in question has a drain tube (red circle), make sure it is intact on both ends.

[surrender]

Cool! I knew what the bypass cover was, just could figure out how to check for leaks. thanks

[DargelJohn]

Cool! I knew what the bypass cover was, just could figure out how to check for leaks. thanks

Another way to check the cover for leaks is to have the engine idling on the water muffs. Spray a little WD-40 around the cover. If the idle changes, during spraying, then that is an indication of a leak.