QuestionI have a yamaha YFM-200N 1985 atv.Runs well when you pull start it,starts very hard or will not start at all with electric start, especially when it is cold.
AnswerThis is somewhat difficult to diagnose without actually being able to make some measurements, but I will try.
To start with, if it starts easily when you pull start it you can rule out the ignition, carburetion and compression as possible problems. That leaves only the electric starter circuit.
I would start by loosening and re-tightening the connections on both ends of each cable between the battery and the starter motor, including the battery ground cable. You wouldn't believe how many problems are caused by oxidized connections.
NOTE: Disconnect the ground cable from the battery before you touch any of the other cables and reconnect it last.
If that doesn't fix the problem, measure the voltage across each cable - from end to end, not from the cable to ground. If any of them has more than 1/2 volt across it while you are pushing the start button that cable should be replaced.
If that doesn't help, try measuring the voltage across the big terminals of the starter solenoid. It should be full battery voltage (12-13V normally and zero when you press the start button. If it is is more than 1/2 volt while you are pushing the button, the solenoid should be replaced.
If all else fails, there is probably something wrong with the starter motor. It probably just needs to be taken apart and cleaned & re-lubricated. If you attempt this yourself make sure you use contact cleaner (not WD40 or penetrating fluid) to flush out the hardened grease and the brush dust and use a grease that is made for electric motors.
