Alright, i just rebuilt carbs and put new plugs in it about 2-3 weeks ago. Very fun, goes about 52 according to the speedometer. The last couple of days have been crazy though. Three days ago, took it out, ran great, went about 50-55 MPH. Two days ago i took it out, and it started right up. When i opened the throttle after letting it warm up for a few minutes, it limped for 2-5 seconds, then topped at about 40. Today, i took it out, and it topped at 20 and went down to 10, and then i was seriously getting mad with it, then i could hear it missing and having trouble idling, so i idled back to my lift and cranked it out of the water and looked at the plugs, and tested cylinders.
Back cylinder - 150 PSI compression - nice brown plug
Front cylinder - 145 PSI compression - black, wet, oil fouled
So, i put in a plug that the previous owner had, and got it to top out at 50 again.
What my question is, how can i keep the front plug from oil fouling?
Back cylinder - 150 PSI compression - nice brown plug
Front cylinder - 145 PSI compression - black, wet, oil fouled

So, i put in a plug that the previous owner had, and got it to top out at 50 again.

What my question is, how can i keep the front plug from oil fouling?