Thunderbolt Ignition Sensor question?

[martys]

I have a 1992, 4.3L, V6, Alpha One, MerCruiser. I had to replaced the ignition sensor during the 2002 season. Since then, it seems like every year and a half, I have to replace the sensor. Today, the engine would not start after water skiing for about 3 hours. Using my MerCruiser shop manual, I trouble shot it and again it's the ignition sensor.
Is this an on going problem with Thunderbolt Ignition systems?

 

[Don S]

Re: Thunderbolt Ignition Sensor question?

No, it's not a common problem. You might remove the distributor and check the shaft and bushings. If they are worn out, the rotor can contact the pickup surfaces of the sensor and damage the sensor.

 

[martys]

Re: Thunderbolt Ignition Sensor question?

I checked the shaft and bushing, both looked good. Inside the distributor was cleaned, the sensor, rotor and cap had no damage. But, I did find this. The wht/grn wire from the distributor to the shift cutout switch was pinched behind the valve cover. Bare wire was exposed and probably touching the motor or cover. Even though this wire is the negative, could this contribute to my problem?

 

[achris]

Re: Thunderbolt Ignition Sensor question?

Yep!

Although the wire is 'negative', it is not ground. Ground it and the ignition system will shutdown... Jee, that's what your problem is... Fantastic, solved....