fc 540v kaw motor

B

blackchevy3de

Active Member
I have a ferris mower with a fc540v motor ,calls for a r n11yc spark plug ,but I keep fouling it after running it for 4 or 6 weeks , its burning oil but for right now I have to keep running it ,can I go to a hotter spark and if so how hot should I go. thanks
 
Blaz could be right unless you make a very small change. To do this you need to compare the plugs' ceramic protrusion (material surrounding the electrode shaft). Theory is the further into the combustion flame the tip goes the hotter the plug is due to the longer cooling path back into the head. Be careful of piston contact. There should be some mfgr charts somewhere on line??? Seems like such changes are usually made due to mixture strength, as in older carburetted race engines sputtering at low speeds. IMO
 
motoman said:
Blaz could be right unless you make a very small change. To do this you need to compare the plugs' ceramic protrusion (material surrounding the electrode shaft). Theory is the further into the combustion flame the tip goes the hotter the plug is due to the longer cooling path back into the head. Be careful of piston contact. There should be some mfgr charts somewhere on line??? Seems like such changes are usually made due to mixture strength, as in older carburetted race engines sputtering at low speeds. IMO
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I did compression test has 150 psi, so I pulled head its hard to tell if gasket is blown ,but there are some signs of that, a lot of carbon on head and valves piston is really clean, I found what I believe to be the problem a bad valve seal. thanks guys
 
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