The main problem with ethanol in rubber fuel lines is that ethanol causes hardening and flaking of the rubber. Long before it ever gets bad enough to leak the little flakes of hardened rubber detatch from the inside of the line and travel down to fuel pumps, injectors, and carburators. Where they clog up all the small metered orifices that regulate the amount of fuel the engine is getting. This can lead to the car just not running or running poorly, to the internal components of the engine breaking or seizing, thus trashing the whole engine.
The main problem with ethanol in rubber fuel lines is that ethanol causes hardening and flaking of the rubber. Long before it ever gets bad enough to leak the little flakes of hardened rubber detatch from the inside of the line and travel down to fuel pumps, injectors, and carburators. Where they clog up all the small metered orifices that regulate the amount of fuel the engine is getting. This can lead to the car just not running or running poorly, to the internal components of the engine breaking or seizing, thus trashing the whole engine.