I suspect that it has sat for long periods with rotting fuel in it. We see this issue a lot here... the 420s have wimpy fuel pumps that overheat and fail while pumping rotting fuel through the filter/system. If this is the case, then the entire fuel system will need to be flushed & cleaned out. The fuel filter will need to be replaced and if the pump is failing (fuel pressure should measure between 48-53 lbs) that will need replacement as well. The injector will need a cleaning too. Its a big job that requires the person to be thorough. Half-hearted efforts are rarely good enough. To prevent this from happening do not allow fuel over 30 days old to remain in the tank. And don't ever put any ethanol-laced fuel in it.
You can find a copy of the service manual for your Rancher linked in the manuals thread HERE.
You can find a copy of the service manual for your Rancher linked in the manuals thread HERE.
