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

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    Senior Member Maverick's Avatar
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    Default What is your process for changing the oil on the 912ULS

    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
    EAA, AOPA
    KF5 (N49FK & N36KJ)
    Phoenix, AZ

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    Super Moderator desertdave's Avatar
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    Default Re: What is your process for changing the oil on the 912ULS

    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.
    Dave
    KitFox 6 Taildragger
    912 ULS
    Whirlwind 70” Prop
    Garmin G3x
    All around nice guy

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    Senior Member Delta Whisky's Avatar
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    Default Re: What is your process for changing the oil on the 912ULS

    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

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    Senior Member jiott's Avatar
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    Default Re: What is your process for changing the oil on the 912ULS

    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.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

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    Super Moderator desertdave's Avatar
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    Default Re: What is your process for changing the oil on the 912ULS

    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.
    Last edited by desertdave; 03-13-2021 at 08:06 PM.
    Dave
    KitFox 6 Taildragger
    912 ULS
    Whirlwind 70” Prop
    Garmin G3x
    All around nice guy

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    Super Moderator Av8r3400's Avatar
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    Default Re: What is your process for changing the oil on the 912ULS

    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.
    Av8r3400
    Kitfox Model IV
    The Mangy Fox
    912UL 105hp Zipper
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    Senior Member Delta Whisky's Avatar
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    Default Re: What is your process for changing the oil on the 912ULS

    Quote Originally Posted by jiott View Post
    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.

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    Senior Member Maverick's Avatar
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    Default Re: What is your process for changing the oil on the 912ULS

    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.
    EAA, AOPA
    KF5 (N49FK & N36KJ)
    Phoenix, AZ

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    Senior Member jrevens's Avatar
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    Default Re: What is your process for changing the oil on the 912ULS

    Quote Originally Posted by Maverick View Post
    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.
    John Evens
    Arvada, CO
    Kitfox SS7 N27JE
    EAA Lifetime
    Chap. 43 honorary Lifetime

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    Default Re: What is your process for changing the oil on the 912ULS

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

    Building 7ss STI x 2
    Oratex
    29" shock monster
    EP912STI 155hp
    Garmin
    N33TF......FLYING!
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