Solenoid!
Welcome worried man!.....but there's no reason to be worried!....this should be a very simple fix. It most likely is your starter solenoid!.....you said you by-passed your switch and it still kept running. Do you mean your key switch, or your solenoid switch. If you jumper across your solenoid and it's bad, providing continuity, then it will continue to draw amps from the battery to run the starter motor.
Do this. If you already know or can trace your positive wire into your electrical box, open it up, you'll see the solenoid. Thats where the two positive battery wires (one from the battery, second one out to the starter) connect to your starter. Remove the battery lead to the starter and touch the other wire of the same diameter to the other post (the one going to the starter). This should spin your starter over. If you have your key on, the engine will start. As soon as you make contact and the engine is turning over (or running), pull that wire away. The starter should now disengage. If your not running water into your engine, don't run it for more than 30 seconds or so. I recommend you have your water running while doing this test. If the starter stops running after you disengage the battery's positive wire from the solenoid and the engine did turn over (or start), then replace the solenoid. There are links on our web-site where you can purchase that item online.
The solenoid is the most likely cause to your problem, but there are a couple other less likely things it can be. If salt water has entered your electrical box. Salt water is condusive to electricity. It will short out the solenoid, causing it to run. If the bendix in the starter is bad, when you start the motor, the starter's bendix will allow the gear to remain engaged to the flywheel. But this doesn't seem to be the case because this only happens when you try to start, not at the time you put the cable on.
Do the above steps to your solenoid and get back with us. Let us know the results.
