E85 gets about 30% less fuel economy in a car than regular gas. 76,100 to 81,800 btu's in e85 (depending on source) compared to 114,000 btu's in gas or 111,000 btu's in E10 (the standard at the mn pump).
E85 does have a higher octane which could let the engine running a higher compression ratio but since it is a flex fuel it needs to still work with gas so the octane advantage is not taken advantage of.
The corngrowers associations have lobbied ethanol so much and that is why it is being used more than the merits of the fuel itself.
To have E85 the mower mfg needs to increase their fuel tanks about 30% to have people actually use them in high production options.
Also if it wasn't for the gov subsidies that discount the E85 it would be much more expensive. Just remember it looks cheaper but you are still paying taxes to pay for it.
Propane without subsidies still makes sense. The fuel savings offsets the conversion costs pretty quickly and the infrastucture is already in place (tank exchange programs, tank filling at certain locations, etc.)
Kohler basically upgraded the ECU, added a sensor to know what fuel is in it, changed fuel injectors to flow more. It's more hype than actually moving with the times.
Looking for blown Kawi 29HP DFI engine's fd791d, whole thing, intake, throttle body, and electronic's. PM me if you have something you would like to sell.