Running with 1 plug wire off???

[<troublemaker99>]

I'm trying to troubleshoot my engine. its a 1999 125 merc. Classic. It starts fine, idles great, and for the most part, runs fine on high end. After it warms up and while running around 3500-4000 rpm, it will miss when you hit heavy chop. Can i pull off a plug wire, one at a time, to see if i can isolate a single cylinder that is missing. Will the boat get up on a plane only running on 3 of the 4 cylinders??? If i can pinpoint which one is missing, it will help to troubleshoot the problem!!

Thanks

[<Mikey>]

This would work much better. Connect an inductive pickup timing light to each plug wire (one at a time) and run the motor. As long as the light is flashing, that sparkplug is firing. You can see misfiring and non-firing cylinders as you're running this way. Running with the plug lead removed can damage the CDM.

[<troublemaker99>]

Would that work even if the miss is for about 1 second. It will miss, then run fine for a little, then miss again whe you hit chop. If it missed on a cylinder for a brief second, would you be able to see it with that device your talkin about??

[<FishNski>]

Do you have any loose wires on that motor that would cause the speratic misses when in choppy water? Just a thought

[<Skeeter Fin>]

None, been through it over and over. I'm at the point where I just need to start replacing components in the ignition system. What would you recommend first. I don't know what else to do!!!