I live in SW Virginia. It doesn't get terribly cold here but I am concerned about starting my 912 when it is COLD. What temperature is considered too cold to try to start my engine?
What preheaters are the best for the 912?

    by » 11 years ago


    I live in central NC which is only slightly warmer than your area. I use idle throttle, full choke, and no preheat on my 912S. Starts great all winter. Sometimes shakes a couple of seconds when its really cold but thats it. Just guessing here, but I would think that a good strong battery is crucial when cold. I also use 50W oil year round. A lighter weight might make for better winter starts but I've never needed to try it.



    by » 11 years ago

    Hi Albert,

    Part of this answer would depend on whether it was in a hangar or outside.
    If the engine turns over without any issue then it isn't to cold. If it drags and has a hard time starting then it's getting too cold.

    Watch this video.

    When the temps start to hit freezing and below then it may be time to pre-heat. For you guys that get down into the 20's and below then it's certainly time to pre-heat. Some use 100W light bulbs, some room heaters to blow warm air and even hair dryers. Hairdryers my favorite. :P
    If you are trying to fully warm and engine with some of the above you may keep the chill away and may keep the outside skin warm, but may not be doing anything to heat the engine deep inside where it needs the heat like the cylinders, pistons, rings, bearings and crankshaft.
    Ideally you are looking to do is to warn and heat soak as much of the engine block, oil and coolant all at the same time. Some times just using those warm air heaters that blow warm air up into the cowl and cover it with an insulated blanket is enough to keep the cold out and at least not let the engine chill too far.
    There are to heaters on the market we hear about. Reiff and Tanis. Tanis has been around for ever and is pretty much the gold standard other heaters are judged against. I'm not a huge Reiff fan because they took a wet sump heater system and tried to adapt it to a dry sump. I would say it is average. They put a heat pad on the oil tank and a small heat pad on the bottom of the engine.
    Tanis on the other hand still puts a heat pad on the oil tank, but uses screws that replace the rotax original screws with heating elements inside them. There is one for the bottom of the engine and one screw for each cylinder on top of the engine. 6 heating points verses 2 for Reiff. The Tanis does a better job of getting heat into the entire engine especially the cylinder area and crankcase. The Reiff is $270 and the Tanis is $635.

    I live in Tucson, AZ and don't need a pre-heater, but if I lived in cold country a Tanis would be under my Christmas tree for sure.

    I have installed 12-15 of the Tanis. The guys that go out on those 10F mornings say the engine temp is already 75F-80F on the gauges before they even turn the engine over.
    The engine starts just like it was summer time. Cranks right over and the warm up period is shorter.

    I hope this helps some.

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


    by » 11 years ago

    My Rotax is heated year around. 6 hrs ever morning. I have a Tanis on the engine. When I get there and pull the plane out it has 130 degree indicated. The plane starts smooth ever time. I'm a big believer in keeping it warm. I have seen many engines destroyed because of lack of oil pressure when it is cold. Or not getting enough oil thrown on parts in the motor and cam lobes going flat because lack of oil.


    by » 11 years ago

    I live in Austria, where it gets down to about -5 °C (about 20 °F). I don't have a pre-heater. Neither do any of my hangar mates (about 10 gyroplanes, all with 912 or 914). And we do fly in cold weather.

    On pre-flight I turn over the prop by hand a couple of times. I don't do it too much so that some oil still remains in the crank case. I like to believe that this will assisst in lubrication during the initial starting phase. The hand turning is supposed to get the oil moving a little bit and get a fresh film of oil between the surfaces.

    From then on I follow exactly the cold start procedure outlined in the manual. I was able to get it running every time. I keep the starter engaged for a maximum of 5 seconds or so. If it doesn't catch, I'll let it rest for a minute and try again.

    Once, on a really cold day, the oil pressure started out OK but then dropped down to 0.7 bar. I knew the oil level was OK because I had checked it before. So I just kept RPM at 2000 and watched the oil pressure closely. As the oil temperature started to come up off the peg, oil pressure normalized quickly and I advanced rpm to 2500 until the oil temp saw 50 °C.

    The mag check will regularly give me 250-300 rpm drop for both circuits. When I repeat the check after landing (just for interest), I got 150 rpm drop. The engine runs smoothly, so I am not worried.

    Greetings, -- Chris.

You do not have permissions to reply to this topic.