Aviation octane is rated differently than auto fuel. 100LL av fuel is about 105 auto octane rating,It does need the oil mix for lube.Another good point is you can leave it in your tanks forever and it won't spoil.Can't have fuel in airplanes gumming up !

Joe, I see you are from Houston. There has to be a lot of small airports near you. In some cases, the small airports don't gouge their customers with large mark-ups on AV gas. When we had huge prices on gas a while back, there were occasions where the tank farm at the airport was cheaper than supreme on the streets. And as someone above pointed out, it has excellent shelf life, it is very dry fuel...

The gas docks on the water in puget sound only carry regular and diesel. I was worried about needing fuel on a long run and was looking at octane boosters. I asked my local performance shop about octane boosters and he said he would give me some timing stops so I could back off the timing on the water to run regular. Seems like a good plan if it works. I have twin 2.5 outboards running 135-140 psi at cranking speed.

I was checking the ingredients of the octane boosters in the auto parts store. Seems a lot of them are just some kind of petrolium distallate, probably kerosine or diesel. All the cheap boosters do is keep the motor from pinging, won't give you any more horsepower.

Torco, purchase it by the 5 gallon can. A quart for every 25 gallon.

ok..first I am not nor do I claim to be a blown boat motor expert, but I built and raced seriously modified 2 strokes in the desert for over 15 years. I have a motor that made 15 hp stock and makes over 50 reliably now. anyways in reguards to fuel...any off the shelf octane bust is garbage. you might go from 89 to 89.9maybe 90 and inconststantly at best. you got a boatload of money tied up, dont risk it trying to save a couple bucks on fuel. the only reliable way to make significant increases in octane is to mix fuel. sure its a hassle but, much less hassle then rebuilding a motor. with what gas costs at the fuel dock, race gas really isnt that much more expensive. especially when bought in bulk (min. 55 gallon barrels) if you buying a couple hundred gallons you might even be able to get it tanker delivered to the dock and pump it in..so you can spend 3.50 a gallon at the gas dock then pour in walmart mega duty race gas concentrate 104 octane boost and pray or spend $4.50 a gallon for some decent 110 octane trick, vp, etc fuel and mix 50/50..when mixing 50/50 find the middle number than subtract 2..not an exact science but will give you a comfortably safe number. fuel has a lot of science to it...octane alone isnt the magic bulltet everyone thinks it is, theres specific gravity of the fuel, resistance to detenation, flame rate, burn temp etc..with out a major science lesson..lets just say that adding race fuel to pump gas will make your engine much happier than dumping a bunch of paint thinner in it (toulene) of some snake oil off the shelf octane booster. yes offshore and off road are apples and oranges but I didnt get 3 world endurance records by skimping and cutting corners, you make a commitment to big power, you make a commitment to good fuel and added maint.

and av gas??? EEEEKKKKKKK!!!!!! av gas is formulated with all sorts of stuff including anti icers, and formulated for motors that run an consistant moderate rpm level with thin air at a steady load..when was the last time your boat ran like that?? and for the above mentioned race gas, dont get it at the track or a service station, if you will be buying quantity and on a regular basis go straight to the distributor/ oil company you will save a buck or two a gallon.

Joe, Maybe You Could Check With The Sunoco Plant In Pasadena About Buying In Bulk.

LOL!

I don't know anything about AV gas... I will do some looking. Wonder what Mercury says.... Needless to say, I will want to stay in warranty.

I know the Galveston Yacht Basin only does mid-grade fuel.... 89, I believe. I usually fill-up at 3 Amigos before heading out... Which is not an issue.

I'm mainly concerned about running elsewhere (ie: Florida), and not having to run 110/114 at all; rather bringing along a couple gallons of additive in case I get myself into a pinch needing fuel and stopping some place that only has 89. I'd only put in enough fuel to make it to the next place that sells 91/93 (and add Torco etc...).

Thanks for your thoughts. I don't think I'll ever have engines that require anything but pump gas... too much work/hassle!

Joe