Help number 3 keeps fouling

[patricks]

I got a 1996 Kat 600.all stock,It is a project for me and my son,and it runs like a top.But every 4 or 5 days number 3 plug fouls,I am using Auto lite Plugs(1.50$)I know cheep lol..do you think that is the problem..Its done this 2 times and always on number 3 thanx for any info

[Black_peter]

Well I know the NGK's are more (I paid $4.50 last time) but if they work all season....

Why is it fouling? Oil or Gas? Riding or idle? Maybe you have a sticking float?

[steves]

I would only ever use NGKs when NGK was installed at the factory.

Try that first.

[suzukiray]

Do a compression test on all 4 cylinders to eliminate that #2 is a bad cylinder. If compression is more than 20-30 psi lower than the others, it is probably oil fouling. If the compression is good, look at the carbs. You might even have an issue with the spark plug cap causing a weak spark. Troubleshooting these things is just a process of elimination. Good luck, Ray.

[patricks]

compression IS GOOD ON ALL CYLENDERS,WHEN I PULLED THE PLUG IT IS BLACK I THINK ITS THE AIR MIX,WHEN I REV IT UP A SMALL AMOUNT OF BLACK SMOKE COMES OUT.IDLE IT RUNS FINE.I GOING TO GET A SET OF (NGK) RITE NOW IS PART#CR9EK RITE.........SORRY FOR ALL CAPS MY K/B IS SCREWD UP LOL

[steves]

The CR9EK are used in 98+ motors. I think the size is different for Pre.

[hardlydangerous]

I would test the carbs for a leaky float valve causing that carb to flood...
set the fuel petcock to prime and see if it leaks fuel.....

[md86]

Seriously , it COULD be many things . Mine turned out to be a non-stock pilot jet . I mean , who changes pilot jets ? But it COULD be a sticking or dmagaed float , wrong pilot screw settings , missing/worn parts in the carb , sparkplug not seated tight enough , or just a loose plug wire . But wait , there's more .....