I have an old 600AJN with a carbureted Ford 425 in it that has many issues, but the most troubling is the stalling after warm up and surging when you step on the dead man pedal to try and stop it from stalling. Many hands have been on this thing before me and I have found the wiring diagram to be utterly useless. There are splices and bypasses everywhere, but despite this, the machine used to run just fine. It has only started the surging recently, and the stalling once warmed up is why I have it out of service now.