Mercruiser 5.0 carb crank/won't start condition :(

alldodge

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Ignition sensor was replaced White/Red wire is connected and White/Green is disconnected.
White/Green wire is striked rapidly against a ground and there still is No spark?
 

MNugen

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Did the “no sparks” test again and it’s still pointing to bad ignition sensor in distributor. What’s the odd of having new(broken ignition sensor). I’ll order another one and see if third time is a charm. Crazy engine...
 

MNugen

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Ignition sensor was replaced White/Red wire is connected and White/Green is disconnected.
White/Green wire is striked rapidly against a ground and there still is No spark?

There is spark when I strike ground with the white/green lead. According to the test chart, if there’s spark, replace ignition sensor.
 

alldodge

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You have 12V on the White/Red coming "from" the TBV ignition module?

The rotor does have the metal fins which pass by the sensor in the distributor?

The rotor does turn when the engine is cranking?
 

MNugen

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You have 12V on the White/Red coming "from" the TBV ignition module?

The rotor does have the metal fins which pass by the sensor in the distributor?

The rotor does turn when the engine is cranking?

Yes, I do have 12v at white/red wire from ignition module.

the rotor was replaced last year and seems to have metal fins. I didn’t check if it was spinning while cranking, but I have taken the cap off a few times today and the rotor position is at different spot each time. So I assume it’s spinning.
 

MNugen

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Alldodge, I just want to say thank you for taking the time troubleshooting with on this one. I finally got her fired up after changing just about everything on the ignition...except for the cap and rotor. I just replaced them last season and keep on thinking they’re good. Lord behold it was them that causes weak sparks. I changed new plugs and new wires as well. Cranked and fired up....the feeling of joy hearing it runs again. I had to crack open a beer and congrats myself:)

thanks again for the help.
 

Scott06

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I’ve found a spark gap tester like this to be helpful in diagnosing weak spark or no

https://www.tooldiscounter.com/prod...Wj_jlMQXwL3b4NBp9MSU7nyaAELKXz2QaAr-XEALw_wcB

was chasing a hard start and part throttle issue on an old evinrude. I did everything but replace the coils... easy to see how strong a spark you have with this. I used it on every engine I own when they were working well to get a baseline.
 
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