Fouled plugs on Honda 90

[Harry Woodworth]

"My 1999 Honda 90 puts out a l

"My 1999 Honda 90 puts out a lot of carbon in the exhaust water and heavily fouls all four plugs after only about 10 hours of running. It starts and runs just fine. The compression is okay on all cylinders. Previous owner had carbs cleaned and new fuel pumps installed. My Honda dealer cleaned and synced carbs and put in a new thermostat. It still fouls plugs with dark carbon.
I clean the plugs once a month but it's getting old. There must be "something" causing all this carbon. Does anyone have any ideas? Thanks, Harry"

 

[scotho]

I would like to hear this answ

I would like to hear this answer also. I have a 40 hp with one fouled plug and carbon all over the motor.

 

[mike step]

"I'm curious as well- I ha

"I'm curious as well- I have a 15 hp 4 stroke that is fouling plugs and kicking down to 1 cylinder intermittently.

Assuming coil, but the engine is only 4 yrs old..."