1994 40 HP Mercury firing problem

[ALGF311]

A few days ago I ran it for about 5 min and she shut down, I let it cool for awhile and she would go for another 5 min. Got home pulled the cover off and found that a couple of wires coming from the voltage regulator had gotten real hot. So I put a new voltage reg on it today. It started and ran for about 30 seconds and shut down, tried it again and same thing, ran for a few seconds and shut down. Now she will not fire up at all. I need suggestions. Thanks

 

[Little Richard]

I hear I bad regulator usually fails from poor grounding to battery or a bad battery and once it fails can cause over heating on your stator. I'd test that one and check your battery and ground cables and clean them if dirty. After that go to the basics check spark plug with gap tester at 7/16 inch if spark is steady and good. Pull plug see if your getting fuel (wet plug) inspect plugs. That will point you in right direction. Ignition problem or fuel

 

[ALGF311]

Update. Went back out there after about 3 hrs, she fired up and I ran her for about 10 min. I felt of the voltage reg and it was to hot to touch. I shut her down. I'll clean my cables in the morning and see what happens. Please let me know if there are any more suggestions.

 

[Little Richard]

I don't think the regulator itself is the reason it won't stay running. If this new one is ruined already I just don't want you to damage the stator under the flywheel. Google CDI electronics trooble shooting. You can test you regulator with a voltmeter. Definitely clean all connections on battery and check voltage on your battery and make sure it's good too. But once this is done and regulator replaced if needed again. Buy an adjustable gap spark tester from autozone. $8.00. And check that spark jumps the 7/16 gap consistently. Especially when the motor is shuts down. That would indicate your ignition system is working. And you can focus on fuel delivery and compression. Sounds like fuel issue.

 

[ALGF311]

Thanks L Richard, it did not stop running on its own this time, the VR got so hot that I shut her down. It got hot enough that 2 sec touching would be all I can stand.

 

[ALGF311]

It looks like a new battery is going to fix the problem.