I been burning 91oct with no alki. now with the price of fuel going up I might go back to burning with alki. it never hurt my engine. I change oil every 50hrs and replace the filter. I always pull the top off the tank to clean it out and fill to within about a 1/2 inch from top. very easy to do, I never replace the o ring. I have a flap that I pull out on and the clamp comes off, pull the inside out and set to the side with a rag under it. I don't disconnect any hoses. the screen inside I pull out and put in a pan on the floor. I take a suck gun and suck out the fluid and put it into a 1 gal jug left over from the previous oil. I get down to the bottom plate and pull that out and suck out the rest of the oil. I take a couple blue rags (Costco) and wipe it out looking for any particles, so far none. I put oil in the tank to the level it was when I took the top off. I now pull off the filter and take the new one and fill it up with oil. stick it on. done. I can do it real fast, within a 1/2 hour. I don't purge any line because I never took any off. long time ago I measured what come out of the lines and the amount was so small, not even a 1/2 cup. I take the plane out of the hangar and crank it over for no more than 15 seconds, I wait a few second and crank again. the oil pressure will come up. I stop, let it sit a bit. crank it again to make sure it's got pressure. now I turn on the mags and let er rip. starts up and got pressure for oil right away.

now with all this said and done, I don't like an efis for oil pressure, I like manual all the way and I like mag switches not an ignition switch. I can crank and not have it start.

now for 100LL, that stuff is nasty. It needs to be replaced. I hate it in my RV with the io360 and it's a nasty thing in the rotax. I know whats killing the get rid of 100LL, those boys with the big engine out there, they want lead and high octane. us boys are on the back burner. money speaks today.

I run auto fuel in my rv also. this engine has over 1300hrs and the top end is nice and Purdy.