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1996 Mercruiser Alpha 1 4.3 v6

F

frankrodgers12

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Okay I ran great for 3-4 trips out this Spring but on last trip the engine sputtered then died and now will not restart. I thought I had is traced to the coil however I replaced the coil and still no spark. Fuel delivery is good at carb. I need to know opinion on what some of the experts think may be the real issue here.
 
Check Kill Switch at helm if you have one.

I assume you have the factory thunderbolt ignition- go through this trouble shooting guide on the ignition https://bpi.ebasicpower.com/faq/MERCSB92-11.htm

Most of the time the coil is fine, rarely fail.

Also worth ensuring the distributor shaft is turning and the pin holding the gear on the bottom of it is still working
 
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Okay. My controls are panel mounted and I can't see how to remove them to do a kill switch over ride to diagnose this. Cap and Rotor are fine but I have heard this kill switch from a few people now.
 
The Kill switch is actually called a LANYARD switch.

It is supposed to connected to the driver by way of a tether line in case he falls away from driving so the engine shuts down.

What controls are you talking about?
Where is your shift control? Is it mounted to the side next to drivers seat or mounted on the dash/helm?
 
frankrodgers12 said:
Okay. My controls are panel mounted and I can't see how to remove them to do a kill switch over ride to diagnose this. Cap and Rotor are fine but I have heard this kill switch from a few people now.
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With key in run check and see if you have 12v on positive side of coil.if yes then the kill switch etc is working . If not need to look for why
 
I believe I have a bad ignition sensor as the kill switch is now bypassed and I purchased a new coil and it is installed. I have checked distributor it seems fine.
 
How old is the cap/rotor.... I never get a third season out of one in a salt water environment... cap never looks "that" bad, but replacement seems to be the only fix.
 
frankrodgers12 said:
I believe I have a bad ignition sensor as the kill switch is now bypassed and I purchased a new coil and it is installed. I have checked distributor it seems fine.
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Did you run through the troubleshooting sequence that was linked and it pointed to the ignition sensor ? You have 12 v on positive side of coil ?
 
frankrodgers12 said:
I do not have 12v at coil. So will a motor turn over and not fire with bad ignition switch?
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It might but I'm not sure off hand. I know at the cannon plug you get 12 V supply from #6, you need maintained 12v on #5 purple for iginition, need momentary 12v on #7 to engage the slave solenoid and thus starter.

here is a link to typical dash wiring https://www.perfprotech.com/blog/articles/mercruiser-engine-harness-schematic

Is this something you can read through and trace out with a voltmeter or test light? Not trying to be disrespectful just trying to asses your skill level so we can help.

Pay attention to purple (ignition 12 v supply too pin 5) and red/purple (12V supply) as I've seen these where it wires to the gauges power in series so you have several connections to get loose or get corroded, which is poor design. If you are on the water and you gauge doesn't get who gives a sh$T but if your ignition does not get power because it goes through five gauges ...

Willing to bet you have loose or corroded connection or the inline fuse is popped
 
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