I recently bought a used 2000 Tohatsu 15 HP (M15D) and am now finding controversy over the sparkplug. An owner's manual didn't come with the engine, but the PDF version from the Tohatsu site lists a plain, old NGK B7HS-10 as the plug of choice. The engine had BP7HS-10 plugs installed when I got it. The local dealership mechanic now tells me I need to run a "projected tip resistor" plug (BPR7HS-10) to get easiest starting and best running. The NGK and other plug websites agree with the mechanic in listing the BPR7HS-10.. I can accept a "projected tip" argument, but I was of the opinion that the "Resistor" was related to an electronic emissions issue and only required in certain places like California and Canada ... but that's an area in which I am woefully ignorant. I'm sure they'll all work, but how do I determine who's right ... the downloable owner's manual or the current opinion consensus ... B7HS, BP7HS or BPR7HS???