Carbon removal recommended by Mercury?

[Nova Kaw 650]

If you're doing everything you're supposed to- and you're fining big loose chunks of carbon in the exhaust, there is a problem that you're not aware of. Often revealed in an Air/Fuel Pressure Test (and pressure leakdown test).

Pressure too high on one or both?

[bighaida]

i blew my head gasket in some hydrilla, it over heated, my Yamaha was twelve years old. When I replaced the head gaskets the pistons and walls looked brand new, not a speck of carbon. I bought the motor new and used Amsoil since it was 4 months old. It's fake oil so no carbon buildup. Been using it since the day I got my 225 Mercury. Six years later no problems. I can't believe people still use the old oil when the synthetic is so much better. I use Amsoil in my trucks, boat and yard equipment for the last 26 years with zero problems. Don't change, it's good for the economy.

[EuropeanAM]

Pressure too high on one or both?

Air leak, fuel leak, or high pressures on either. Good idea to record precise results for each of the following:

-At idle
-Under Acceleration
-5 Seconds after shutdown *
-10 Seconds after shutdown *
-15 Seconds after shutdown *

* Acceptable to restart engine for each of these tests.

[Nova Kaw 650]

Air leak, fuel leak, or high pressures on either. Good idea to record precise results for each of the following:

-At idle
-Under Acceleration
-5 Seconds after shutdown *
-10 Seconds after shutdown *
-15 Seconds after shutdown *

* Acceptable to restart engine for each of these tests.

I'll take it to my local dealer in the spring for a pressure test.
There was literally 1/8" or more of carbon buildup in the upper part of the tuner, again, with only about 20 hours on it. Runs good otherwise.