If you're using fuel with castor oil in the lubrication mix, the engine is probably still fine.  If you're using 100% synthetic, then it's tough to say.</p>

As long as the engine will still run, it isn't "ruined" or anything, so don't sweat that too much.</p>

I saw a similar situation at our field a week or two ago where a pilot was having a heck of a time breaking in a new O.S. .46 LA on his Kadet.  His top end would rise and fall and he couldn't keep the engine running reliably.</p>

Like 90% of all "engine" problems, it turned out to be problems with his plumbing (fuel lines and tank setup).  The tank was actually set up pretty good, but the lines to the carburetor were too long.  He had too big of a loop going from the clunk line on the tank stopper to the rear needle valve intake, and the upside down "U" portion wasn't drawing enough fuel reliably.  He also had too much line going from the rear needle valve outlet to the carburetor intake, and it was bulging out a bit in a sideway "U" shape.</p>

We had him trim about 3/4" from the tank to the rear needle valve and about 1/4" between the rear needle valve and the carburetor.  We fired it up, retuned a bit, and his engine is running great now.</p>

My advise is to go through your fuel lines and tank setup to make sure there isn't anything restricting the flow of fuel.</p>