CajunMooneyguy

Ok guy......heres a real puzzle for all you gear heads out there!! I have a 1967 M20F, IO-360 fuel injected 200hp. two weeks ago on my way to Tenn from La, after 2 hour of smooth running .... the engine started running rough with a subtle drop in rpm (by the sound of it) ....not "stuck valve rough"....but a noticable vibration. It would do this for 8 or 9 seconds......then run smooth like nothing happened. after a minute or so, the cycle would repeat. Also....while it was running rough....at the same time, the cabin would fill with an acrid exhaust smell. almost like a exhaust/raw fuel/running rich smell. SO......of course i set it down asap. On the way down I tried troubleshooting to gather info for the mechanic. I tried both mags, tried full rich and max leaning, boost pump on, swich tanks, various power settings, and Nothing made a difference! All of the readings/pressures/temps, on the EDM 711 engine anylizer were perfect, no changes, heater was off. The ONLY abnormal (besides the smell and rough running) thing was....while running rough for the 8-9 seconds....I would get a slight "RISE" in fuel pressure from 25.5 psi to 27 psi! then back to 25.5 when running smooth. Once safely on the ground, I did run ups and checked everything again. Still did it, even at idle!! and sitting there in the sunlight i could actually see the white smoke/exhaust coming from the firewall while it would run rough. The lineman said he could see a "mist" coming from the engine breather tube when running rough. And it did in fact puke more oil on the gear door than usual. OK....so the mechanic didnt have a clue. I was stuck in Louisiana and he and the plane in Savanna Tn for a week.. He put a new set of plugs, new engine/mechanical fuel pump, cleaned the injectors and line, checked every thing for leaks, compression test, cleaned fuel filters, and basically, checked every thing he could and said it all checked out great! So, a week and $1,200 later i pick it up and head to La. Ran smooth and solid like i was used to.....for a little over an hour, then started doing the exact same thing!!!! AARRGGGHHH!!!! So, I landed in Greenwood Miss yesterday, and there it sits! HELP!!!! Has ANYBODY out there had this same issue and what was it??! The old man behind the counter at the FBO told me his buddy had a very simular problem and it turned out to be badly pitted points in the mags! Makes sense? Please help if you can! Throw it out there. Ill try anything! Thanks!!

Hi. What viscosity oil are you running? 15W50? Try running a straight 50 wt. it makes sense that the oil pressure drops a little with hotter oil.... But it shouldn't KEEP dropping to Zero! Does it ever stabilize "in the green"? What is the time on the bottom end? It's a common sign of excessive main bearing wear to have low oil pressure while the engine is hot and idling. Oil temps of 240 and mildly above, wont necessarily hurt the engine, as the oil still will retain its lubricative qualities..... But temps above 240 will drastically shorten the oils lifespan. 25hr between oil changes instead of 50 are recommended. Now.... As far as oil loss.....my bet is its going out the breather. Try an Air/oil separator. The condom blew off because of the crankcase pressures, but an air/oil separator will catch the oil mist and vent air overboard. It has a drain at the bottom and can be used to recover the blown out oil. They cost anywhere from 2-400 bucks. Google it and/or look up "Aircraft spruce and specialty" and search for it.

Yep. You absolutely right. I thought that price was "each" and didn't realize it was so long. Money well spent! Thanks to all!

Does anybody know what those parts look like? Specifications on them? If its a simple doubler I'm sure I can make my own parts "equal to or better than". Any idea what the windows cost? Is there a vertical steel tubing member behind the interior plastic panel?

Do I have to have an STC to put a one piece back window in my 67 M20F? It doesn't really fall into the "major modification" category. Not structural, doesn't effect performance etc.... Maybe just a logbook entry? And is there a source for buying the plastic or will flat wrap Lexan do?

Hi. Yes, I just bought my '67F and it came with an extention. Im flying tmor (king air) but will try to remember to go grab it out of the mooney and get dimensions and post it for all. But....Its pretty straight forward. just a 12'' piece of pvc with a T at one end and a notch cut out of the other that fits over the selector handle. Todd

Ok.....first, My plane doesn't have the yoke vacuume release button....it's got a panel mounted push/pull switch to "engage" the PC system. Problem is when it's engaged.....it starts an insidious very slow roll to the right no matter what I do with the roll knob on the turn coordinator. Any suggestions? Also....when the system is (supposedly) off, and flying straight and level, when I go to turn left it feels like the yoke is blinded or stuck just a tiny bit for a second, then it "breaks loose" and it's normal after that. ME NO LIKEE!!

Great replies all! Thanks. I really prefer the "looks" of the three blade and the previous owner said the two blade was indeed louder and rougher. I'm ok with losing 3 potential knots to gain climb performance. My plane is a '67 M20F, and it has the tail fairings, wing tips with hidden antenaes, one piece windshield, wing root fairings, gap seals, lower cowl closure, and wing and flap hinge fairings. What other speed mods are there out there that I can install.....besides 201 windshield and cowl? I'm planning on those soon. I know there is a belly pan for the Cs, what about the Fs?

Im pretty sure It's a McCauley. The last guy painted over the prop stickers at annual a week ago. I'm in Tennessee till Wednesday and when I get home ill check the logbooks. Thanks!

Has anyone heard of Mooney wings breaking in flight? Is there any "typical" place that corrosion will show up first?

Hello all. Newbie. First post. Just bought a '67 M20F. It has a three bladed prop and I love the looks and feel, but I'm reading a lot about the 2 bladed prop being faster, lighter, smoother, cheaper, etc... Why have the 3 blade prop? Can someone share the pros and cons of each? Is it worth converting back to a 2 blade? Is my 3 blade prop worth anything on the used market? Thanks in advance. Todd

Hey guys.....first post. I bought a '67 M20F last week and love it. It has the wing root fillets, tail fairings, gap seals, wing tips with internal antennas, one piece windshield, lower cowl closure, wing and flap hinge fairings, cleaned up IFR "T" panel, and a 3 bladed prop. Manual gear. It's a joy to fly and already have 11 hours on it. Getting 156 kts at 5500ft. 25/2500, power boost on. Smooth air. 10.2 gph. My question to anybody that cares to comment is........ I've heard that the 2 bladed prop is better in most every area than the three bladed. I love the looks of the three bladed, but is that the only advantage? Should I consider a two bladed? Top prop? Can anyone outline the pros and cons of both? Is there a market for my 3 blade? Thanks in advance! Todd