[masraum]

Originally Posted by rockfan4

I found this interesting. Never thought about it before, but if you use a gas pump with one hose, the gas in the hose is whatever the last guy selected. If you're only buying a gallon for the mower, half your purchase is past the selector, in the hose and the pump.

I'm still using a Korean war era 5 gallon can that my father used, so I buy 4 - 5 gallons at a time, but I'm going to start going to the station with multiple hoses on the pump.

Is it really a problem with the mower. Do you use anything but 87 octane in the mower, meaning the cheapest, lowest octane fuel that is sold? So the only possible impact would be that you'd get some 89 or 91 or 93 octane mixed in which shouldn't be a problem.

When I get gas for the mower (we mow ~4 acres), I fill 4 cans, 3x 5gal and 1x 2.5gal. But I don't think having half a gallon of 93 in the 2.5gal can would be any sort of issue.

My understanding is that the detergent package at one of those stations is the same in all 3 octane ratings, and presumably the ethanol content is also potentially the same.

Getting a ˝ gal of 87 in the boxster with the other 16.5 gal of 93 is not likely to be an issue.

I don't see the problem (unless your mower runs on 93 octane and you use a 1gal gas can).