sounds like your android valve on the engine is not working. It puts a little extra fuel to the engine at a low RPM so it won't die when you engage the machine. The right person can just shut it off and then the only thing you will notice is that it will smoke a bit more on startup and when you excellerate. It won't add to the top end power but will the bottom end. It could be as simple as the line from it to the pump is damaged. The higer RPM you have your rotor running will also demand more HP on startup. Hope it is simple.