4.3 Mercruiser Briefly Stalls but Then Continues On

[kmdickinson]

I've got a 2005 4.3 TKS that had an issue that I can't seem to find anyone else ever discussing. Yesterday my 4.3 suddenly stalled but then just as suddenly resumed operation. It happened twice. Once in my driveway on muffs while engine was at idle and then again on the water while at cruising speed. Both times it had sounded as if the ignition key was turned off for a half second before being turned back on. The one on the water happened within the first 5 minutes of operation. I kept going for another half hour or so hoping that it would happen again but it never did.

The engine runs great otherwise. It has all of the power and acceleration that it ever had.

I've read up on all sort of problems hoping to find this as a symptom but none list this type of "stall" as a symptom.

Since it sounded to me like a total lost of ignition, my thoughts on possible causes:
a. The coil is slowly dying
b. There is a short in the kill switch
c. There is a short in the wiring to the ignition key
d. There is an issue with the shift interrupter

Any one of these problems is a cheap fix. My problem is how would I diagnose it?

Any thoughts on cause? Any insights into other areas I can look at?

Many thanks for any assistance.

 

[Bondo]

Ayuh,.... Welcome Aboard,..... I'll go with b, or c,.....
d could do so, but Only if shifting when it happens, which would indicate the lower shift cable is failing,.....
To diagnose b, 'n c, used the shake, wiggle, pull test,.....
Good luck,....

 

[Scott Danforth]

It's never the coil (except in 3 out of 1 million)

Most likely bad connection unless you were shifting

 

[kmdickinson]

Thanks. I'll concentrate on the ignition and kill switch wiring and see what happens. Hope this is something I can isolate. It was quite the butt pucker factor having that happen at cruising speed.

 

[flashback]

Maybe a shot of water in the fuel?