I have a 1994 440 with twin 3116...

[GST1]

I have a 1994 440 with twin 3116 Cats,

At 1500 rpm, both engines  will drop back to 1000 rpm, then comes back up then drop again. 

Runs perfect under 1500

Ideas? Fuel is fresh, fuel filters have been changed 

[gtstang462002]

Do the motors have electronic controls or mechanical? Will they run wide open throttle under a load, how about no load(neutral)?