2000 J70vlsis intermittent RPM loss

[echotango]

My J70 intermittent problem is, you can be running 4500rmps and drop to
3500 rpms. Top cylinder not firing, you can run and hour or more before this
happens. These parts have been replaced over the last few seasons, spark
plugs & wires, coils, carbs rebuilt and end of last season a new power pack.
Boat was used two times for about and hour each time and ran right. First time
this season boat ran for about and 1 1/2 hours before dropping rpms. At times you can stop motor for a few minutes and boat will ran. Can anyone help on this problem, at wits end. I mix my oil VRO disconnected.


ET

[boats.net]

Probably need to test source coil, trigger coil and CDI output voltage with a peak reading volt meter(DVA meter) to see if all are within specs at the time of loss of rpm to see if it's an ignition problem or to rule out an ignition problem.

[echotango]

Thanks for the reply,however, I traded the boat in for a new Key West 1520
Sportsman with a 50hp 4 stroke Suzuki. Problem solved!!