I recently purchased a 1996 RANS S-7 with a 912UL engine that has had the Extra Performance 95 HP piston kit installed. The plane has not been flown since 2000 and only has 150TT. I have tried to read through nearly every post on this site and would like to make sure I have some of the tune-up specs correct.
The specs I have in the paperwork all not all that specific.

Plugs called for are: NGK DCPR8E gapped to 0.22

Idle speed states 1400 RPM but everything I seem to read states I should set it closer to 1700 RPM.

I bought several Rotax oil filters and a case of the Shell Sport oil.

I removed both carbs and cleaned them, changed oil, etc. to bring this engine back to operational status. It runs great....let me rephrase...it RAN great until last night. Got some type of issue with one of the electronic modules that I will inspect to a greater depth today.

What are the thoughts on the "Soft Start" module from BullyHawk? I am new to these Rotax engines and it sure seems to stop rather abruptly. It has a two blade taper-tip Warp prop. This engine has the 4-pin electronic modules. Actually I am having an issue with one of those also and I posted a question on it in a different thread.

Anything else I should know about this engine.

Thank you,
  • Re: Tune up specs

    by » 13 years ago


    Low idle speeds are hard on gearboxes, especially with the higher horsepower engines. I idle my ULS around 1800rpm. The idle is much smoother there.

    The Bullyhawk soft start module is well worth the money. Cheap too, compared to Rotax parts. Can be bought in the four pin or six pin model and is easy to install.

    The rather sudden stop when the engine is shut down is normal. Lycs or continentals usually stop pretty suddenly also if you stop them by cutting the mags. Thats why they are almost always stopped by pulling the mixture to full lean and letting the engine die gradually with the mags on. You can ease the sudden stop a little by killing one mag, wait a couple seconds, then kill the other mag.


  • Re: Tune up specs

    by » 13 years ago

    Hi Keith,

    It sounds like you have a 912UL (80 hp) that someone converted to a 95 hp. The plug for the 912UL is a DCPR7E and the 912ULS is a DCPR8E. Th gap is the same. It should be .023 - .027. Narrower gap for your cold weather. I don't know enough about the engine mod to know if that company wanted the other plug (DCPR8E). Your engine doesn't have a slipper clutch, but it may have more compression now than original. 1400 rpm for idle is too low and 1700 rpm will make your engine happier especially if the compression has been raised. If those carbs have never been rebuilt I guarantee they need to be just for the "O" rings alone. They will be trash. The float needle has been upgraded too. The rubber parts in the carbs including the rubber diaphragm will not be in good shape and too dry to function properly or not fail in a flight. Think about getting them rebuilt. I would.
    The start and stop is probably a little more abrupt than you are used to, but normal for the Rotax.

    I would get on this site and download all the manuals.
    Operations manual,
    Installation manual,
    Line Maint manual,
    Heavy maint manual,
    Parts manual

    You will need all these from time to time. Many don't think they need the parts manual, but besides the parts it has many special torque values in it too.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

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