What are all the signs of a bad crank seal? If one is bad will it make the fuel pump not work? Our 86 indy 400 will not stay running,it runs for 30 seconds then dies,usually fouling the pto plug. Sometimes it will run for a couple minutes but idles up to 3000rpm then down to 1700 then back up to 3000. It also seems to run good at 3/4 to WOT throttle. All I can really think of is that it needs a fuel pump or a crank seal,wanted to see if anyone else has had these issues or can help narrow it down.