black plugs on merc 225

[dpf-01]

i just got a 1988 EFI 225 Merc Laser and after running it i notice that the ends of the spark plugs are turning black. this can't be normal right? anyone ever had this happen and know whats wrong?

[terry taylor]

The electrode end? How was the engine running [ok] did you idle it a fair bit? Is the fuel fresh thanks.

[dpf-01]

ya, I use 92 no ethynal fuel and yamalube, its oil injected, I only idle from the dock out deep enough to takeoff. then i'm doing wide open passes across the lake. the motor starts, idles, running great...till the plugs get too black.

[terry taylor]

And then what happens?