Fuel Consumption - Overhaul Break-in

I have been following the run-in instructions provided with my engine overhaul. I have about 5 hours on the engine at this point. I am flying between 4500-6500 feet full rich which is a lot lower altitude than normal -- between 8500 and 11500. The plane is an RV-6 with a carbureted O-320 and a fixed pitch Sensenich cruise prop. At 75-85% power the fuel flow is 12 gallons per hour. Does that sound in the range of normal? I have just never run the plane like this.

Thanks,
Hank

Hank,
That fuel flow at full rich and full throttle in that altitude range is normal.
Even though you are breaking in the engine it is OK to lean a little but be sure to stay at least 150 deg rich of peak egt.

Keep a close eye on the other temps to be sure they are in normal range.

And follow the Lycoming break-in procedure, when they say to run it hard go ahead and do it you won't hurt the engine.

These engines are designed and can safely run at full throttle for as long there is fuel in the tanks and the temps are in the proper ranges.

So put the spurs to her and let her run. Your reward will be a tight, strong running engine.....that's the way it worked for me.

Glenn Wilkinson

Thanks for the reply. Even though it doesn't feel right, I've been doing it. It's not much fun on bumpy days like today. If I lean like normal the oil temperature rises above 200 to about 215. If I stay full rich the oil temp stays at 195. CHT is just below 400 degrees.