daveb Posted June 21, 2008 Posted June 21, 2008 Hi 720 will not start I pulled the plugs to check for spark and i only have spark when i let the key go to run when it is in the start position no spark , that doesnt seem right is it? thanks for any and all help . this sight is great. thanks Dave
dentwizz Posted June 21, 2008 Posted June 21, 2008 The ignition is magneto based, so the "start switch" is in fact a grounding terminal when in the off position. Otherwise they are open. To test this function, use a continuity checker and test between the switch and the coil-grounding wire for continuity. If there is continuity in all three positions of the switch or as the symptoms would suggest, in run and off, then a new switch may be in order. They generally don't cost much anyway.
D-17_Dave Posted June 21, 2008 Posted June 21, 2008 sorry Josh, but the 720's are not magneto based. They are powered ignition systems like a car. The ignition switch is most likely bad Dave. It must supply 12 volts to the coil in both the run and start position.
daveb Posted June 22, 2008 Author Posted June 22, 2008 that was what i was thinking Dave thanks for the reply . i will check the switch later .
arnoldir Posted June 23, 2008 Posted June 23, 2008 Hey Dave, My buddy has my 720 so I can't just go have a look-see, but it sounds like the main 12v line to the coil has gone. My ford pickup did this to me years ago, only ran when key was in start position. Ford uses a resistive wire, Chrysler uses a block resistor. When key is in run position, the voltage to the coil is limited by the resistor to about 9V. When cranking the starter, the 12V to the solenoid is also sent to the coil to bost the spark when cranking. The 720 is likely simmilar in how it is wired with 2 feeds to the coil, one for start, one for run. Good luck
Willy Posted June 23, 2008 Posted June 23, 2008 Ck your starter solenoid. Run a jumper from your battery to the plus side of your coil and see if it will start if it runs ck the wiring from solenoid to the sw. to the coil. If it good run a continuity ck on your sw. if its good you can bet it's your solenoid.
daveb Posted July 2, 2008 Author Posted July 2, 2008 Hey guys Thanks for all the responses . Put a new ignition switch in from local auto parts store and tractor starts and runs better know than it has in the three years I've had it. Also fixed a few problems that was starting to be a pain. Switch and plug were both corroded and 2 wires pulled out of the plug. Thanks again. Dave
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