I moved this to the Gehl forum where it's more likely to be seen by people knowledgeable in these.if it was idling and went full throttle I would look at the governor ,look also at the oil level in the engine if it is way high it could have been fueling itself. smell the oil does it have a diesel smell.
Thanks I checked the solenoid and is working I think it may be the governor? looks like I would have to remove the entire back of engine off to get to the governor?I moved this to the Gehl forum where it's more likely to be seen by people knowledgeable in these.
Did it shut down normally, or did you have to stuff something in the intake? A runaway won't shut down with the key, so I'd be more in agreement with foton as to a governor issue. Could be as simple as a linkage came off and it went to WOT.