Barry,

I ran my engine as slow as 2200 RPM during 2008-2009; then increased to a min of 2300 when the bulletin came out on this. I now cruise at 2300 RPM most of the time, increasing to 2400 when I want to go a bit faster/run a higher power setting.

(I normally run LOP at 2300 RPM/29" MP/14.0 GPH fuel flow, and take what IAS that yields. That's generally 80 LOP on the richest cylinder and 100 LOP or less on the leanest...this changes with temp and engine RPM)

Bob

PS: Now at 1050 total engine hours, but had to replace a cracked crankcase (around #1 cylinder studs) at 520 TT, so really not a 1,000 hour engine. I have run it LOP, except for TO & climb, since it was broken in at about 20 hours TT.



For no particular reason, I was browsing through the Continental Engine Maintenance and Overhaul Manual (M-18) for the TSIO-550 family of engines.  The engine specifications are listed on pages 2-22 through 2-33.  Each of these engines has a "Minimum Cruise RPM" of 2300 RPM.   I was unaware that there was any RPM restriction (other than max. RPM) on these engines.

I never go that low.  My minimum cruise RPM is 2400.

Does anyone use a cruise RPM below 2300?

Barry Knotts
LIV-P, N4XE