Bob, I have a similar situation with my P70 in the R-54. I only have access to the plug if it's in the bottom quadrant of the engine. I asked Jet Cat about this, relating that the manual states the plug should be within the upper quadrant. They told me that it would be OK near the bottom but I might see shortened plug life because the plug will tend to accumulate more combustion debris in this area. To date I have the original plug installed and have had no problems with starting.