09-20-2017, 12:04 PM
(09-20-2017, 11:01 AM)tinboatcapt_imp Wrote: I had never thought the poor mileage on the first tank after winter storage was due to the fuel stabilizer. In this neighborhood, winter storage is four to six months. I had always chalked it up to evaporation. Pump gas has a measurable percentage of 'low boilers' that evaporate fairly quickly. Less fuel burns to get to the "I need gas" point on the gauge. Compounding that is that the remaining mix is ... well ... 'gunk'. On my personal bikes, I have been known to drain the tank and pour the 'gunk' into my pickup truck.
A trick we used when we had demo bikes and others stored at the dealership*, was to use 100 octane avgas. It's not legal for street use, but enough to keep the system wet and start a bike for a customer. (Also, the bike will run REALLY well on it.) Avgas is specified to remain stable for six months. Those 'low boilers' could be a problem in an aircraft at higher altitude by causing vapor lock. Something not of great concern in a vehicle.
*A short stint as Sales Manager.
jim
Avgas is extremely stable compared to auto fuel. Unfortunately, using it in a modern vehicle could be disasterous. It gets its high octane from large amounts of tetraethyl lead, which will destroy catalytic converters and oxygen sensors in short order. Even in older bikes, long term use in an engine that doesn't have high compression pistons will eventually lead to unburnt lead deposits gumming up the valves.
That said, I used to use avgas quite successfully in my old Mercury convertible with a high compression V8 (originally spec'd for 98 octane auto fuel). Ironically, at the same time I had to burn 87 octane auto gas in my old Cessna with a low compression engine (originally spec'd for 80 octane avgas).