What is your process for changing the oil on the 912ULS

[Maverick]

After reading Eddie's comment about changing the oil at about 35 hours when flying on 100LL, I began to wonder how to go about doing this. It was simple with the C-O-200 but the location of the oil reservoir of the 912 seems like this is going to be a bigger effort. How do you do your oil change? What are the steps you take?
Fred

[desertdave]

I disconnect the two hoses from the oil reservoir, remove the reservoir, take the top off, dump it, clean everything inside, reassemble it and reinstall it. You can change the oil wearing a white tuxedo and not get a drop on you. Easiest oil change ever.

[Delta Whisky]

Dave - I've read mixed reports on disconnecting the oil hoses in terms of necessitating pressurizing the tank after refill to ensure the pump has oil to it. Do you do anything special after refilling the tank? Thanks, Darrel

[jiott]

The oil tank never has any pressure in it; it is vented to atm.
Rotax recommends that you hand turn the prop thru 15-20 blades after oil change is complete before engine start. If you disconnect the hoses from the tank, tie the one to the oil pump up so it doesn't drain out; the one from the bottom of the engine doesn't matter.

[desertdave]

I always turn the prop till I hear the Rotax gurgle before starting so it sounds like I’m covered.
As for not letting the hose drain, Desertfox4 normally holds it up and mocks me during the entire process all while drinking a Dr Pepper.

[Av8r3400]

Mine is a model 4, so the tank is high and behind the engine. Removing the tank to dump it is not really do-able, so I take the top off the tank, syphon out the oil, then wipe out the tank and components with a shop towel, change the filter and reassemble the tank and fill it.

I have separate ignition switches from the starter switch and crank the engine without ignition until I get oil pressure. Check again for leaks, then start the engine. Done.

[Delta Whisky]

The oil tank never has any pressure in it; it is vented to atm.
Rotax recommends that you hand turn the prop thru 15-20 blades after oil change is complete before engine start. If you disconnect the hoses from the tank, tie the one to the oil pump up so it doesn't drain out; the one from the bottom of the engine doesn't matter.

Sorry, it appears my question needs additional detail. The reports I was referring to were discussions related to SI-912-018r1 in which some folks said that they felt that the SI, para 1.5, indicated the system should be purged if the suction hose had been removed. This requires pressurizing the tank. It appears that holding the end up IAW your and desertdave's technique keeps oil in the hose (as opposed to completely removing it and allowing the oil to drain out) and prevents a vacuum break. Now, if I could get Desertfox4 to come over when I have to do my next oil change, all will be well. I'll even supply the Dr Pepper. ;) Thanks for the responses as I need to clean out my tank (as a 100LL user) during the next change and was pondering this issue.

[Maverick]

I have ignition switches. I hand turn the prop about ten times then spin the engine with ignition off with the choke on for 5 seconds. Let it set for 10 seconds then turn on the ignition. It usually starts up right away. On colder days I might have to spin it twice to get started. Desertfox4 and Murle recommend this procedure. I think this would get the oil where it needs to be.

[jrevens]

I have ignition switches. I hand turn the prop about ten times then spin the engine with ignition off with the choke on for 5 seconds. Let it set for 10 seconds then turn on the ignition. It usually starts up right away. On colder days I might have to spin it twice to get started. Desertfox4 and Murle recommend this procedure. I think this would get the oil where it needs to be.

I’m trying to figure out how using the “choke”, which isn’t a choke in the conventional sense, could have anything helpful to do with this. Seems as though it could add additional fuel into the intake system, but why, before you’re actually trying to start it? Please educate me.

[Shadowrider]

Makes sense to me. Kill two birds with one stone.

[Maverick]

Murle told me using the choke with the non-ignition spin works like the primer on a Continental. It atomizes fuel in the venturi. This is with no throttle so not much fuel is available. When I turn ignition on i advance the throttle 1/4 inch. Engine starts smoothly at circa 2500 rpms that I bring back to 1800 until I start to see the oil temp come up then i warm up more at 2000.

[jrevens]

Thanks for explaining, Maverick. I hadn’t really been aware of any starting problems... maybe I’m just lucky. It gets kind of cold here in Colorado sometimes, especially up in the mountains, and I honestly haven’t had any problems with starting. I apply the “choke”, throttle closed or cracked just the tiniest bit, and it starts almost instantly - every time. I am in a heated hangar that’s kept at 40 deg., I have the same results though when away from home, parked on a cold ramp. Knock on wood.