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So the RPM reading on my previously beloved EDM-900 went nuts last week. It works ok at startup, assuming the plane has been sitting for a while. Then at some point in cruise flight, the reading starts fluctuating wildly (it's definitely the monitor system - not the engine or governor). Then it stops reading outright and indicates the big red X. I had two different mechanics look at it briefly on the rather long, 8 leg trip I took last week but they couldn't do much. The rpm sensor that goes in the inside bottom vent plug hole of my right mag (Bendix) is very hard to access and may require pulling the mag to check it fully. It looked ok with a mirror and feels secure. One of my stops was at Oshkosh, where I got to ask Joe Polizzotto, the CEO of JPI, about it at their exhibit booth. He said it wasn't a common issue that he was aware of, but happened to have a new sensor on hand and gave it to me. He also said that it could be caused by the magnets in an old mag getting weak - I'm not sure I totally get this - could the problem really be intrinsic to the mag? My mags did have their 500hr service 6 months ago. Questions: 1. Anyone with similar experiences out there that got addressed? 2. Any other guidance to give my avionics shop when I take it back to them to swap the sensor? I will be very frustrated if the sensor gets swapped and I still have the problem- it can take up to an hour to show up in flight, so I may be back home before I know if the fix worked.

Alright Mooney group bear with me, this may get a little long winded. New Pilot and even Newer Mooney pilot. So, i just finished my 15 hours to be checked off by insurance. I now have about 20 hours in my new (to us) 1967 F model. We bought it with about 25 hours on a new engine, and just completed our first oil change as well. Lots of firsts going on here. So, I am new to complex aircraft as well. When performing our run up we normally lean the mixture to best power similar to what we did in the 172. Run up to 1800 rpm, full forward on the prop, and slowly lean until power loss catch it and give a few extra turns once the power is back. Then we pretty much haven't touched the mixture on any flight. I played with it a little the other day in cruise, lowering it until it got rough and then adding it back in until it was smooth. Our checkmate checklist says cruise around 2600 rpm on the prop, but once setting the prop you cannot use RPM as a good lean indicator correct? Plus to add to complication our fuel pressure gauge is out (so I cant just put it at the bottom of the green) which would be running it efficiently correct? (Also new avionics coming in a couple months) So the only time I have tried to lean it in flight was in a cruise the other day I leaned it until it ran rough, then twisted it back in to run smoothly. Which the POH says don't lean the power above 75% power... but at full throttle I am sure I am above that. Did I hurt the motor? How on earth do you calculate percentage of power? Then there is the throttle. I figured on a brand new engine you wouldn't want to run it at WOT all the time due to wear on a new engine. But my CFI said run it full and manage RPM and Fuel flow with the mixture and prop, but my Dad (Airforce Pilot/commercial pilot of 30 years) said he would also be worried about wear on the engine, but thoroughly admitted I probably have more experience in a civilian airplane than him at this point. Ours is also turbo normalized as well, and all I have been told about it is to keep it below 28 MP. All of this has added a ton of confusion in my mind, so I went to the internet. Specifically another post on here: Which added even more confusion. I also realize I probably sound like an idiot, but I am okay with that if it helps me figure all this out by asking the experts. So to summarize my questions: 1) Is our best mixture practice during run up correct? 2) When leaning for efficiency, can you use RPM drop with a constant speed prop, fuel pressure indication, or leaning it until its rough then adding it back in? Which is correct or are all correct and some are just better than the other. 3) Is WOT the correct way to fly? Is the POH out of date as stated in the message board above. 4) Is 2600 RPM that the checkmate suggests the best cruise setting on prop? 5) Have I hurt the engine buy leaning with full throttle in and potentially getting over 75% power setting? 6) How on earth do you correctly measure % of power? (This one is probably easy but I am missing it) 7) Does any of this change when adding in the turbo? Thanks everyone!!! I know that is a lot to follow but any response, guidance, or videos would be much appreciated. Fly safe, The FNG

A 1981 M20K's POH says run-up at 1700 RPM A 1980 M20K POH says run-up at 2000 RPM What says Mooneyspace M20K owners with the TSIO360 engine?

Hi Everyone, I am having a problem with my JPI that I cannot find an answer too here or elsewhere. The RPM measured by the JPI, EDM-800, is reading double the Tach RPM. I have checked the connections on the sensor (Bendix Dual Magneto Magnetic Pickup) as well as the cleanliness of the sensor pickup and all was good. This problem was intermittent, was gone for a few months and now has returned and I repeated my connection check without luck. Does anyone have experience with the JPI doubling the RPM sensed? If so what had you done to resolve it? Thanks for looking. Mike

Help! As mentioned in another thread, I've been facing prop overspeed beyond 2700 rpm red line - on the ground all seems fine but when airborn and oil gets warm the prop overspeeds (noticed 2 times during initial climb). I had governor overhauled but it did not solve the problem. So I did the test described in Lycoming SI 1462A and...it failed (I did it with engine at ambient temperature but I dont think it impacted the results anyhow). So, I got the prop dismantled and inspected plugs at the crankshaft end - seems like they both sit tight. Next, I machined tight plastic cap with gasket, bolted it to the prop flange and made Lycoming pressure test again - still no pressure buildup and distinc oil gurgling heard inside the engine case. Then, I disconnected hose delivering oil from the governor to front of the engine case, pluged the fitting in the engine case and supplied air pressure through the plastic cap bolted in place of the governor - also no pressure buildup and oil gurgling inside the engine :-( Any ideas what else I could check to find cause of the issue other than worn front bearing requiring splitting the engine?! Any suggestions more than wellcome! thanks in advance, Marek

Basic question- sorry if it has been covered here ad nauseam- search function was no help. Neither was searching the lycoming O-360 operator's manual. What is the optimal idle speed setting on my carb for my O-360-A1D? On the ground at full rich, mine idles at around 800, goes down to 700 with the carb heat on, and runs pretty smooth at either speed. I ask because lately I seem to be getting long floats even when I nail my speeds, and I wonder if I'm making too much power at idle. I'm not in the habit of checking my gauges when I'm over the numbers, but I did on Saturday- my rpm read 850 after pulling the throttle to idle. I typically turn off carb heat on short final in preparation for possible go around. That float seemed endless though my airspeed was 70-75 as I started the flare. Could have just been the variable and gusting winds, or my being a crappy 250hr pilot...

I just purchased a G model (for those unfamiliar, the medium-length fuselage with the C-model's O-360 180HP carb'd engine). My issue is with the correct power settings to use. I came across this article by Bob Kromer that makes a pretty compelling case for cruising at full-throttle, 2500rpm, 50 degrees ROP all the time above 3,000 feet. Seems like decent advise. I flew a M20F before I bought the G model and it seemed to work well. My issue is that I'm pretty unhappy with the CHT's these settings give me in my G. I don't have any of the cowling mods (nor does the G model have cowl flaps) so the engine definitely runs pretty hot. My normal procedure has been to lean to 400 degrees CHT, which is usually richer than 50 degrees ROP. As a result, my fuel burn is not exactly wonderful. Recently I've been trying my cruise at 2,400 RPM instead of 2,500. My temperatures are WAY better, it allows me to lean out quite a bit more, and I've noticed the fuel savings. I think it's costing me a knot or two, but I feel a lot more comfortable with it. I do not have a fuel totalizer nor digital engine monitor (just the factory analog single-probe EGT/CHT gauge), so I can't really run a detailed comparison. Has anyone had similar experience, and what do you think of the lower RPM in cruise?

For Sale: RPM Pickup for JPI Engine Monitors. I had this installed in my M20J until 2015, when I replaced my engine from the IO360-A3B6D (i.e. Bendix Dual Mag) to the IO360-A3B6 (i.e. conventional Slick mags). I posted about the experience in this thread: http://mooneyspace.com/topic/15898-m20j-io-360-a3b6-conversion-experience/#comment-221002 The sensor worked with both my EDM-730 and EDM-830 engine monitors.The attached photos show both the unit itself and a picture of it installed on my plane. It's just a loop of metal with wires on it--hardly makes a difference whether it is "new" or "used." But of course I will honor returns if for some reason it doesn't work for you (you pick up return shipping cost). The attached graphic shows a screen-grab from the JPI website, and an excerpt from the installation manual. You can see that the new unit goes for $395. (!!!) I am selling this unit for $200 + UPS ground shipping. If interested, please email directly at dhc@jpl.nasa.gov Dan

I've had my M20C about 6 months and had never flown behind a constant speed prop prior to this, so I don't know what's normal. After I level off for cruise, I usually set power at 23 MP, 2300 rpm. Then I futz around with trim and mixture for a bit. When I'm done with this, rpm usually reads about 2350, and then I pull it back again to 2300. It might drift up again to 2350 one more time, and then generally it stays put after pulling it back again. But yesterday I was surprised to notice it had come up to 2400 about an hour into the cruise during my scan- I may have neglected checking for a while, but it had never drifted so far off before. So to test the governor, I pitched up firmly and slowed to 120mph IAS. Then I pitched down and came up to 170mph IAS - 20 mph above my cruise IAS. The governor did its job and held 2300 rpm like a rock the whole time. My question is - is the amount of drift I am seeing in cruise concerning or in the range of normal? It has a Top Prop which was installed in 2011 but the last governor overhaul that I can find in the books was in '97.

Guys, please, I need your help! I'm willing to buy this tach (http://www.ebay.com/itm/B-D-TACHOMETER-P-N-0520-003-/171348387858?pt=Motors_Aviation_Parts_Gear&hash=item27e528e812&vxp=mtr) to replace mine but I was told that my sender might be damaged. Do you know what is the correct P/N for the sender of it? Does the sender includes the Tach Gen? Any of you have a spare one? It is difficult to find? My IPM says tha TACH GEN (B & D INSTR) P/N is 880053-501, but Mooney P/Ns make me confuse... I'm attaching a photo of the one I removed. Thanks!!

Hello everyone! I'm looking for a tachometer for a 1989 M20J MSE, 28V, IPM says it's P/N is 880039-515, anyone have a spare one? My hole is 2-1/4'' And still, how can I find a tachometer compatible and aprooved for my plane? And if it's not too much to ask, could anyone explain to me the difference between TSO, PMA and STC? Thanks!

During runup I noticed the mag drop to be at 200RPM on the left side. After leaning the engine at higher RPM and allowing it to run for about a minute, the drop remains between 100-125RPM. Most people I spoke to suggested that I might have had fouled plugs so I replaced them all with Tempest UREM38E (massives). After running up with new plugs, the RPM drop was normal but the engine ran rough on the same side (left). I also noticed that when full throttle is applied the RPM does not go any higher than 2500-2600. Has anyone experienced this before that might be able to shed some light as to what might be going on?