"burping the 912 ULS"

by in General Tech Discussion 8 years ago

I have a couple of questions for those in the know. First, is there any other reason for burping the engine other than for checking the oil level? Second, If I burp the engine to go for a flight but at the last minute have to cancel it, if I then go for a flight 3 days later do I have to burp it again? Thx. for any help.
Terry

Re: "burping the 912 ULS"

by David HEAL » 8 years ago

David HEAL

23 192 440

I use the burping process to generally assess the compression of the individual cylinders - not an exact measure, but it will identify an unusually soft cylinder. Once you burp the engine, the majority of the crankcase oil will be in the oil tank so the oil dipstick reading will not change between flights.

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Re: "burping the 912 ULS"

by Roger Lee » 8 years ago

Roger Lee

128 5.28k 4.98k

Hi Terry,

The gurgle will help with two things. One is to get a better idea of the oil level/volume in the tank/engine. This is not exact so use it as a guide and a trend. You shouldn't be using oil between oil changes unless you have an internal engine issue which you can usually tell or a leak. Both usually show up with oil all over the bottom of the engine or oil in the exhaust pipe and or a smoking exhaust when running..

The other reason dates back more years when we had different oil filters and some aircraft MFG's didn't mount the oil tank in the proper relationship to the engine. Some like Kitfox mounted the oil tank too high and with some of the older oil filters oil could seep back and into a cylinder. This would cause a hydrolock situation because oil won't compress and it would bend things if you turned the key and tried to start the engine. Turning the prop through a few revolutions allows the pistons to move and you would find one that was full of oil because it would come to a stop. With newer filters and better engine setups this for the most part has faded away, but some of the older engines setups and with people using non Rotax filters this could still happen. There is no reason or excuse anymore not to use the proper Rotax oil filter other than someone is just cheap. Some engines seem to keep more oil in the bottom of the crankcase and require more prop rotations to hear he gurgle. Perfectly normal.

If you gurgle the engine one day and don't fly for a few days the oil level didn't change unless you see a big puddle on the floor. Not a good sign, but not a likely one.

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

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"burping the 912 ULS"

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