Power cutting in and out

[RFP1016]

I have a 725 D with a 72 inch deck. The power is cutting in and out with or without the blades being egaged. The engine speed drops way down, then comes back up to normal speed, then drops back down again. Any ideas?

 

[bertsmobile1]

Called surging
Search Surging
It is the same for every brand of engine or brand of mower unless you have a fuel injected engine.