skydvrboy

I got the 125 ROP from 100 ROP being best power and trying to go a little more on the rich side. My '67 model owners manual is in the plane at the moment, but the plane came with (only) the '68 model owners manual. That shows cruising at 5000', 2500 RPM, 22" MP, leaned to 100 ROP, I should be burning 10.2 GPH and going 160-163 mph. That is the speed I'm getting, but I'm not burning anywhere near that much fuel. I don't have anything that shows fuel flow, just taking the total gallons to fill the plane divided by the hours flown. So all phases of flight and ground ops are included. Next time I take a longer trip I will have a full tank in one wing, switch to it after I get set at cruise, and then run it for an hour. That will give me a better cruise burn. I will find and study Target EGT.

First post of a new Mooney owner. Don't mean to hijack this thread but I have a similar question that I haven't found an answer for. My M20F was built in '66, but has a '67 SN, so I'm not sure if it has the twisted wing. I've only flown it 25 hours and only a few flights over 1 hr, but my fuel burn seems too low. My first hour fuel burn (startup, taxi, runup, takeoff, climb to 6500', cruise) was only 11.1 gallons. That was with throttle full forward, prop at 2700 for climb, 2500 for cruise, mix 125 ROP for climb, and 50 ROP for cruise. My first full tank averaged 8.8 GPH for all phases of flight and my second was a whopping 8.045 GPH. I have been throttling back to 22" MP when below 5000' for cruise or descent, but otherwise, throttle wide open and most of my flying was 7500' and up. Is this normal? My flight instructor is concerned with the low fuel burn that I may be running too lean and could damage the engine. My TAS has been around 165 mph at '9000 give or take a bit and the plane has lot's of speed mods (cowling, windshield, flap gap, aileron gap, wing root leading & trailing, tail faring, brakes rotated, and more). The rigging is a bit out, but based on all the comments, it seems I should get a bit more speed, but also burn more fuel. Should I be worried? Thanks for the help.