912ul Hydrolock

[tinturtle]

I stopped flying my 912ul at the end of May. Had to leave town to work. Came home in Oct and hand pitched the engine and all was fine. Did not start in Oct. Got home to stay lately. Went to roll over the eng by hand and no go. I pulled the plugs and crankcase oil came out of the two back cylinders. Can anyone tell me what I am up against? The engine has less than 200 total time.

[Av8r3400]

What model airplane do you have?

The early 912 installations in the Kitfoxes have the oil tank mounted high and behind the engine. These installations have the possibility to hydrolock when oil goes past the oil filter into the crankcase.

One of the main reasons for this to happen is using an oil filter that does not have an anti-drain valve. The newer model Rotax filters (825-706 and 825-012) have these anti-drain valves to keep this less likely to happen.

Not impossible, but less likely.

[Planesmaker]

Don't be concerned as Av8r said, if oil tank is high oil will fill the sump. Had the same thing on my 914 when left for several months. Remove lower plugs and turn it over by hand, cleanup the mess, reinstall plugs and continue to wind over by hand till all oil is back in the tank, might even be a good idea to bleed the system if oil tank was drained. Tom

[tinturtle]

Sorry it took so long to get back. Thanks for the tips. I thought there was a plausible simple explanation.