Burping

It is the same for my new 912ULS, after 20 rotating, no burp… my plane is a Aerotrek A220 with 80 hours since new…

Some additional information will be helpful;

 - Engine hours?

 - Describe, in detail, your "burping" technique?

I can get my, just under 200 hr, 912ULS to burp in under a complete prop rotation.

This is because I burp my engine after the last flight of the day, when oil hot. The hot oil is easily moved/returned to the tank.

I burp again before the first flight of the day 2-4 SLOW compressions.😈

If you have to rotate the prop more than someone else to get a burp it just means you have more oil down in the crankcase to move back to the tank. It will eventually burp. yes some burp after a couple of turns and some take about 20+ turns. If you have no hydra-lock and your oil level is up where it should be on the stick then getting that last little bit of oil into the tank or raising the oil level another 1/4" isn't an issue. If you live in cold country and the engine is cold it can take a little longer to burp.

Every engine is an individual. Some burp in 3 turns, some 8, some 12 some 20+. There are a few factors that do influence this.

It may be a minor issue, but I have been told by Rotax trained repairmen that it is NOT a good idea to burp a hot engine after the last flight of the day. Rotating the prop by hand tends to wipe oil off the bearing surfaces and cylinder walls and it is not replaced very well by the slow turning oil pump. Yes, it keeps tappets full, but other critical surfaces may sit for days, weeks, etc. with a less than optimum oil film to protect against corrosion. Better to leave alone, and burp just before next flight.   

Sorry James Ott but your  "Rotax repairman"  I can not agree with this unlikly statement..

The burping of a hot engine is merely taking advantage of the oil being a little easier to force out of the crankcase, back into the oil tank. It will have no detrimental effcets on lubrication or corrosion inhibiting. 

There may be a small additional benefit in hot burping, in that the oil is being circulated to bearings/surfaces to speed their cooling, after engine shut down.

Engines that are not run for long periods of time, are likly to suffer from oil slowly draining from surfaces, resulting in the potential for accelerated wear at start up, however this will not be prevented by not doing a hot burp.

You should have noted that I also do a cold burp (happens to be shorter after a hot one) so oil is being circulated by this action, prior to starting the engine.😈