If you run 35% do you need to back it off or down (turn the motor over by hand the wrong way) the motor after a run and second do you need to back it off or down the motor if it does not start on the first try? sorry I know this does not make any sence! to me too
thanks for your time
steve m.
Regardless of percentage, avoid having anything leftover in the cylinders when you fire. The higher the percentage, the more risk of an explosion but even lower percentages need to be treated with respect.
Spinning a wedge head type motor backwards does nothing...just remove the plugs and windmill the motor to spit it out. You can also squirt methanol in the plug holes to dilute anything in there and then spin that out too. A must at high percentages.
Windmilling a hemi type motor with the plugs out doesn't do much to remove fuel. Backing it down (the plugs are out) is the way to do it.
Starting up on another fuel and changing over is the safest way to fire up, but isn't practical at lower percentages. In my opinion, the most practical way to start with lower percentages is to begin with a motor that's void of left over fuel, then prime with gas (pump or squirt bottle) so that it fires right up. If you're cranking and cranking and it isn't firing, abort, dry it out, figure it out.
Drying a system out is pretty quick and easy...just remove the fuel supply hose to the barrel valve, blow everything into the motor (open and close the throttle a few times while blowing) then spin the motor (windmill it or back it down) to get the fuel out. Rinse and repeat if you like.
Another risk besides starting is a crew guy putting a wrench on the crankshaft to check valves or something and having something go off. We remove the spark plugs at the top end of the track and they stay out of the motor until we're ready to fire or head to the lanes. The plugs are like the "fuse" for the bomb...as long as they're out, bad things can't happen. Only put them in when the motor is dry and everything is ready to go, wrenches off the crank, mag is grounded, etc.