5.7 Mercruiser Ignition Sensor

[KevinCasey]

My boat runs I just thought as ugly as my ignition sensor is I should replace it so I bought a new sensor and it has 3 wires compared to my old one with 2. I have the bullet connectors and the instructions say just plug them in. It mentioned nothing about what to do with the black wire. When I did I didn't know what to do with the black wire and so I just made sure it wasn't touching anything and the boat won't start with the new one. The order is reversed on the order the rotor wheel passes the two wires. The wht/red is female and wht/green male like the old one. When I reinstall the old one it runs.
I tried to post a picture of the 2 but I'm not sure it worked.

Thanks in advance for any help

 

[dubs283]

Re: 5.7 Mercruiser Ignition Sensor

the black wire on the new sensor goes to ground, preferably the same stud on the block as the battery (-) cable

 

[Don S]

Re: 5.7 Mercruiser Ignition Sensor

The black wire is a ground. Just hook it to the nearest ground you can fine.

White red goes to white red, white green goes to white green. Don't switch them.

Do you have Thunderbolt IV or V ?????

 

[KevinCasey]

Re: 5.7 Mercruiser Ignition Sensor

It's a 350 magnum alpha one in a 1994 Chaparral but I don't know if it's a Thunderbolt IV or V and I didn't notice where it said. Sorry.
Thank You for the quick replies.

 

[Don S]

Re: 5.7 Mercruiser Ignition Sensor

It would be a Thunderbolt IV in 94

 

[KevinCasey]

Re: 5.7 Mercruiser Ignition Sensor

It worked.Thank You for your help.