How long between starts needs prop oil burping?

Thankyou for your response, i was under the misunderstanding that it was either relieving air (burp) or purging oil out of the top of the engine, you can tell i have much to learn!

I've done the slow turn & mine starts gurgling almost immediately, but what i have noticed esp. when its cold, (< 70*) it seems to start easier w/ less gearbox banging about.

Im still puzzled why the oil level goes down w/ burping.

We're lucky to have you and Roger assist us understand a bit better our wonderful engines.

John Wrote:

... I'm still puzzled why the oil level goes down w/ burping?

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If you do the Slow Hand Burp the oil level should go up.

You are pumping very little Oil and producing a lot of bypass gas as you pause at each max compression.

If you are trying to burp by running the starter with the Mags OFF, the level will go down.

If you turn the engine quickly without the cylinders firing, you will be pumping a lot of Oil and producing very little bypass gases because you are not making very much pressure and not pausing to allow time for that minimal pressure to leak into the crankcase.

Hand cranking makes less than 150 psi. Cruise power might be making over 1,000.

 Talk about a belated reply... ... but stumbled over this old post and did have a comment:

Roger wrote ".....Even if you burp it it isn't always accurate. It can lie at times. If it seems too low, but wasn't the flight before and you have no signs of leaks or oil in the exhaust then start it for a few minutes and check it again..."

Yeah.... We've had that happen often. Burp completely, check oil, and it shows, say half way down the stick and so we'd add a bit of oil to fill mark. Check again later and it would be OVER the fill mark. Like Roger said, it sometimes lies. So we've learned NOT to add oil under that scenario. Oddly, sometimes just letting it sit for a few minutes (while doing other parts of our preflight) after that false "half-way-down" reading .. check again, and oil is up to full mark on the stick. Can't figure out where the extra half-stick of oil hides and how it seem to be coming UP into the tank while we preflight.

I am curious; how high is your oil tank relative to the oil pump?

I don't know exactly where the oil pump is. sim in answer to the question I'll report my oil tank height like this:

The bottom of my oil tank is , if I remember right (I'm not at the hangar) about at sparkplug level.

The top is about at the level of the carb air filters.