Re: 45 merc no spark
To test the switchbox you need something called a DVA voltmeter. But you can do simple ohms tests on the remaing components. If they check okay, it's the switchbox.<br /><br />But we can also eliminate a lot of possibilities based just on the information you provided. You tested the coils and that should eliminate them. They wouldn't all fail at the same time either, so we can definately rule them out. The triggers operate in pairs, so you have two. You can ohms check them, but it's also unlikely they'd both fail at the same time. So that should eliminate them.<br /><br />Next step is to eliminate the kill circuit. Find the black wire with the yellow stripe and disconnect it. Ohms check the harness side with the dead-man lanyard in place and the key on, there should be no continuity to ground. You should get full continuity with the key switch off or the lanyard removed. Next step would be to wing the motor over with the b/y wire still removed and check for spark. But since your problem is intermittent, I wouldn't rely on that test. What I would rely on is that if it stalls on you again and it runs when you disconnect that wire, then you can expect an intermittent problem in the key switch, lanyard switch, or harness.<br /><br />That leaves the stator and the switchbox. You can ohms check the stator. You'll need a manual for this. It could be bad even though it was recently replaced. If that tests good, replace the switchbox, but only after you've checked for good clean ground connections anywhere there is one. Hope this helps. Good luck.
