Spark Plug Info For Our Birds

[scumdog]

Sorry, I wasn't aware you had a problem. Are you the gentleman with the mixed plug useage?

http://www.gnttype.org/techarea/engine/plugs.html

Can you identify your plug deposit(s) from the chart? You are positive you have the correct heat range? Is this BIRD an export or US model?

KULTULZ, yes, I'm the 'gentleman' with the fouling problem who is using mixed types of plugs -NGK AP6F S and Champion RF9YC. Not sure if they are the correct heat range - any ideas?

The deposits don't LOOK too bad (sooty) but the motor stumbles even under idling conditions but SEEMS to pick up a bit when warmed up, I suspect a few easy highway miles might see it back to normal.

The 'bird is ex Oregon, (I didn't know there was an 'export' model) I bought it while in Salem, it stumbled when I first got it but the new plugs (as above) seemed to fix that however lately it is back to square one. (possibly all the shenanigans with the faulty carb-spacer and running rich etc may not have helped)

[KULTULZ]

The CHAMPION RF9YC is one step too cold for you engine. RF11YC is the correct heat range. The colder plug will allow fuel deposits on the plug causing mis-fire.

Dry and sooty is an indication of an overly rich mixture or the ignition system not being able to fire it. Also check your choke adjustment and power valve condition.