sans charge/avec charge
I believe the switch you are referring to is the one that engages the alternator to charge the battery (on mine it still has the original French "sans charge/avec charge" label). I have noted the same tendency for the engine to run into the red zone at full throttle. A couple of things to prevent this that I have learned: 1) Make sure the blade is clean. I have to scrap mine off every couple weeks in the season. Just a little bit of barnicle buildup has a drastic effect. 2) Don't overcharge. I've played with the charger switch while it is running, and cutting the charger switch has an immediate cooling effect on the engine heat gauge, faster than I can believe is a legitimate thermal impact incurred by the reduction in engine load. I suspect that overcharging somehow biases the engine temp gauge to read high. Try it the next time you are out and see if you agree. 3) To check the range of the temp gauge, turn the engine switch back on a couple minutes after you've killed the engine. Don't be too surprised to see it reads beyond the red zone - that uncirculating water has been hanging in there as a heat sink for the whole engine block. It will cool off as soon as you start the engine. 4) Do check the impellar. Its a pain to get that plate off, but if you buy one of those ratchet drivers with a hinge in them, its well worth it. You need to carry a spare impellar and get proficient at taking that plate off anyway. 5) Check your through-hull. Little sea critters love to make their way up there. I sucked some kind of squid-like creature up into it once and had to get it out with a screw driver. Those are all my tricks. The little Renault has pulled me out of a lot of tight spots (50 knot winds last Thursday!), and I'm amazed how rugged the little beast is...
