How do modifications to the intake or exhaust system affect combustion and spark plugs?

Sep 25, 2006 ... The Boating Forum - What causes a fouled spark plug?? - I have a 2003 Yamaha 130hp. One of the plugs has a wet tip with carbon build up. Aug 15, 2006 ... ... causing carbon fouling is your air filter clean and free of oil? If its in bad shape it could be restricting air flow enought to leave your ... May 31, 2018 ... If the spark plugs have a matte black or grey appearance, it could be carbon fouling — something typically caused by a fuel mixture that is too ... Jul 14, 2013 ... I expect that it is relatively new as the motor produces 105psi compression cold. Plug is a NKG CPR8E gapped to 0.9mm. The air filter is clean. Aug 4, 2010 ... ... abnormally rich mixture, which tends to cause the sooting and fouling of the front spark plugs with carbon. As soon as enough soot from too ... Jan 26, 2009 ... * Carbon fouling: Your spark plug will have a black look, and will ... The cause of this type of foul could be caused by a number of ... Apr 29, 2012 ... Thanks Jim. I'll check the air control cable. That sounds like a likely cause. There seemed to be good tension at the lever but of course that ... ... spark plug because the exhaust smelled quite rich. The plug (original Bosch WR7 DDC4 with two earth points) was heavily fouled with carbon. I cleaned it up ... Sep 26, 2022 ... Carbon Fouled Spark Plug – Find Causes & Solutions · A dirty air filter · Faulty fuel injector · Too rich air mixture · Failed oxygen sensor. Mar 11, 2011 ... If the deposit is hard baked-on, black carbon, the result is indicative of use of too cold a plug. ... cause for a lot of fuel going into the mix.