Re: Honda BF75 .... 1 plug fouls up.
Not familiar with your engine. But basicly speaking, it could be the other cylinder is getting water into it, as black is actually a good thing on a 2-cycle engines' plugs...Just not so much it fouls. It reveals sufficiant lubrication. Make sure the plug is the correct plug for your engine (I dunno,so someone else here may have that info for you).<br />Also try touching the block, top and bottom, after a few minutes of running. You may have a blocked port,and the cleaner plug may be on an overheating cylinder.<br />Plugs on a 2-cycle should be changted every 60-80 hours anyhow (just the nature of the beast).<br /><br />Do frequent decarbon cleanings. A good time for this is just before installing new plugs,and more frequently if you idle a bunch.<br />If you have never done this before, chances are it's way overdue. Buy a can of ringfree,ValveTect, or other decarb cleaner, available at any marina,and many auto stores.<br />There are also additives that do the same thing, but I have had problems running the reccommended doseage on my own outboards,as it tends to change the octane of the fuel..Hence, the engine runs like crud.<br />Finally (and most important), run a compression test. It should reveal why rthe clean plug is clean,if there is a problem with steam-cleaning or insufficiant fuel draw.<br />May also be a stuck reed, but this is very very rare.
