When I try to start my mower which is a 17 HP Murray, model # 425007x92B with a Briggs Stratton engine the starter engages the flywheel and starts to spin the flywheel but then stops and won't disengage from the flywheel. I had a battery charger connected to the battery so I'm pretty sure there is enough voltage. I just installed a new engine but the electrical connections with the new engine isn't exactly like the old engine. I have all the wires matched up except one which is a ground wire coming from the engine and connected to a plastic block which leaves one of the wires coming into the original plug in as not connected. Is it possible that unconnected wire may be the ground for the solenoid and should be connected to the ground wire that runs to the plastic block?