"Corky Scott" wrote in message
...
Pete, I'm assuming it's hydraulic lock because the starter cranked the
prop around half a turn and then jerked abruptly to a stop. [...]

I was an auto mechanic in a previous life and have seen hydraulic lock
before. I know no other way of describing it.

Well, like I said, I haven't flown the new C172's, so don't have any
personal experience with that particular engine installation. IMHO, if that
engine IS experiencing hydraulic lock, that's a problem though.

Oil should not be draining into the cylinders. On the 540 engine in my
airplane, excess fuel that gets into the cylinders will drain out the intake
manifold, and then out a valve that leads to the outside of the airplane.
I've made plenty of hot starts, including many that were really flooded
starts (per the technique described by Robert Gary ), and never had any
problem with the starter turning over the engine.

I've never experienced anything that could be considered hydraulic lock in
any of the fuel-injected horizontally opposed engines I've ever flown.
That's not a huge number of different airplane/engine combinations (perhaps
a dozen or two over the years), but it's enough that I'd think I'd have
noticed the problem you're describing if it were common and normal.

I can't think of any mechanism by which you'd experience hydraulic lock on
the fuel-injected horizontally opposed engine that's in the new C172, and I
would think that if you DID experience that, it would be worth discussing
with the mechanic who maintains the airplane.

Pete