adverseyaw

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Everything posted by adverseyaw

  1. adverseyaw

    Today's flight for 2018

    ;-) Likely my CFII on the radio. We had a glider on the runway at Wenatchee as well. P.S. I checked the roster at the B2OSH clinic coming up, saw your name there, so looks like I'll see you soon!
  2. Hi everyone, I'm trying to track down an occasional stumble I'm seeing at idle and through the bottom half of the power band. The engine, an IO-360-A3B6D in an M20J, runs well at full power. Symptoms: every few seconds, a cylinder will fail to fire (or fires softly). The engine doesn't afterfire/backfire. In trying to track this down, I had some fuel injectors get clogged due to debris in the fuel bladders. That work is done but the misfire remains. So far I've: Cleaned or replaced pretty much all of the fuel system (bladders, boost pump, mechanical pump, fuel servo, flow divider, all fuel injectors, all screens). It's clean now, no debris. Pressurized the induction system, no leaks Timed the engine to 20 BTDC Pulled the plugs a few times, they're clear (not sure if my A&P gapped them) Done about 20 runups with pretty much every combination of MP, mixture, and mags. So far, no clear culprit. It misfires at pretty much all mixture and mag settings, and all MP below about 20". In maybe 10% of the runups I do, it will run like a top (no stumbles!) for a few minutes. So I know it's possible for it to idle cleanly. This engine has less than 100 hours on it since overhaul so infant mortality of some part or another may be a factor. Any ideas where to go from here? Thanks much
  3. adverseyaw

    IO-360 misfires at idle and low MP

    I've been chasing the induction leak theory and have had some success so far. After changing the intake gaskets and o-rings, and cleaning up the Precise Flight standby vacuum line and valve, we got the popping to stop at much lower RPMs and get the mixture to richen way up (so much that it barely ran). Clearly, I had big leak(s). I'll be testing the sniffle valve again this weekend to see if that's leaking further air. We only have a few more possibilities. One thing that tipped me off is that I can only pull down to 12-13" MP with the throttle at idle and 600rpm. I found a few YouTube videos showing IO-360s pulling more vacuum at idle. It may be I can only get it this low but high numbers indicate a leak is possible (not guaranteed, but worth investigating).
  4. adverseyaw

    IO-360 misfires at idle and low MP

    That's a good idea. We pressurized the intake already and it held pretty well. Would the gaskets still be likely even if we've preformed this test?
  5. adverseyaw

    IO-360 misfires at idle and low MP

    An overall update: I stuffed a bolt into the sniffle drain valve tube and ziptie'd it there. Ran the engine up but still misses at idle. No change. The plugs are Champion RHM-38S fine wires. My A&P pulled them a few weeks ago and said they were all clean. I'll check the resistance on them soon.
  6. adverseyaw

    IO-360 misfires at idle and low MP

    Interesting. This engine has only 50 hours on it but getting extra air into the cylinder would do this. Good idea, will check. Interesting. The mags were overhauled 50 hours ago, but something was faulty with them causing no ability to start. The prior owner had them repaired right before I bought the plane. Could be a lingering issue with the mags. No problem with hot starts, but there is some occasional afterfiring at idle.
  7. adverseyaw

    IO-360 misfires at idle and low MP

    I think I've got enough to go on at this point. Checking the sniffle valve and sanity-checking the plugs is a good start. Done lots of runups on one mag at a time, no change so far (RPM drop, EGT rise, but no change in misfiring). Haven't looked at condensors, but will see what I can do there. These are all great ideas. Essentially we're eliminating variables in each system: fuel, air, spark. Getting your input helps me find new variables I may have overlooked, like the sniffle valve, which could read fine during a pressure test but could open after it gets jostled by a bit of extra fuel.
  8. adverseyaw

    IO-360 misfires at idle and low MP

    Good idea. The gauge reads well into the green and the problem is present with the boost pump running. Yep, it's there at all mixture settings. :-/ I had the flow divider cleaned, reassembled, and bench tested as part of cleaning the debris out of the fuel system. The problem was present before and after the cleaning, unfortunately.
  9. adverseyaw

    IO-360 misfires at idle and low MP

    Yes! This is very similar to what I'm experiencing. Definitely the first thing I'll check. We haven't cleaned out that valve yet. Will try the sniffle valve and will look at the induction gaskets too. We pressurized the intake and didn't find issues, so I'm not certain it will be a problem, but good to know. ;-) Plugs: will check those next. Not sure what's in there but will probably lose Champions if I find them in there. Air: sniffle valve is the best bet so far. Otherwise no leaks we've been able to find (nor staining -- my A&P has been pretty diligent about that since we cleaned the fuel system). EGT: the probe is in good shape, as it reads fine when we swap connections with another cylinder. The problem is in the line or a connector upstream of the wire bundle. Still working on tracking that down. Runup: yep, I do the EGT check for mags. Good suggestion, my A&P thought the same thing and checked this twice after the servo went back into the plane. We had it even at peak RPM at idle cutoff.
  10. adverseyaw

    IO-360 misfires at idle and low MP

    I don't know. The guy I bought the plane from had trouble with the overhauled servo and sent it out for repair, but I'm missing that document. It may need to go out again. (I would like to pinpoint the issue before sending the mag out, but it's certainly a possibility.) The 1000-1700 was me running the engine up. Any idle time in the trace is time when it was skipping. (In the entire trace I probably had 5 solid minutes of idling.) Good point. I haven't run across the 6/1 second setting in my EDM 830 but will look again and see what I can capture. Will do. We've leak-checked most if it. Good points -- will check into the 1-second setting and will continue to plug away at the EGT4. Interesting. Will look into this. Thanks all!
  11. adverseyaw

    IO-360 misfires at idle and low MP

    The problem occurred within a few seconds of engine start, and continued through the entire data log. The log is about 30 minutes long and the sputter probably happened a few hundred times, most noticeable at idle and at RPMs below 1700 or so. This is off of the Savvy website so could ask them. Getting details on the plugs like you suggested is probably a good first step though.
  12. adverseyaw

    IO-360 misfires at idle and low MP

    I'm running 10:1 compression pistons and do a lot of work to keep the CHTs in check. Unless timing 20 BTDC will adversely affect idle, it's probably a good discussion for another day :-) (Unfortunately the pistons aren't a variable I can change, and I haven't heard of more issues at idle, so for now I'm exploring what I can do with the other facilities on the engine.)
  13. adverseyaw

    IO-360 misfires at idle and low MP

    Went to 20 BTDC per Lycoming SB for reducing CHTs. Those are good suggestions. I actually don't know what plugs are on the plane. I'll check soon. Thanks!
  14. adverseyaw

    IO-360 misfires at idle and low MP

    Yeah, I did a bunch of searching before I posted. Found some threads but nothing that stuck. Most of the ideas were things I've tried. EDM data attached. My EGT4 connection is toast, so unfortunately that data is not useful. Blue line is fuel flow and green line is RPM.
  15. adverseyaw

    IO-360 misfires at idle and low MP

    This one, I take it? Am digging through now, thanks much.
  16. adverseyaw

    IO-360 misfires at idle and low MP

    Back when I was clogging injectors with debris, I was getting EGTs to peak 100-200 degrees on affected cylinders. I've only run it up twice since then, but no notable EGT changes since then.
  17. adverseyaw

    IO-360 misfires at idle and low MP

    I could be talked into that. That said, I've never experienced it on carbureted aircraft I've flown, nor the M20J I got my complex endorsement in. Do others encounter this as well?
  18. adverseyaw

    N201XG comes home

    That's tremendous, so great so meet you @MooneyMurph. 1XG is getting a lot of attention from my A&P at the moment and will hopefully back in the sky soon :-)
  19. adverseyaw

    N201XG comes home

    Hi, everyone! I'm a new Mooney owner -- I recently bought and ferried N201XG, a 1978 201, from its last owner in Texas to my base in Seattle. I decided to buy a plane back in September of last year and settled pretty quickly on an M20J. I did a little bit of looking at Bonanzas and Super Vikings but, as I'm sure you know, the M20 (and in particular the J model) had a really attractive mix of efficiency and speed and features. It also fit my mission profile pretty well, which was generally 0-2 passengers for quick flights within a 400nm radius. The fact that the M20 isn't immensely popular also appealed to me. I daily drove a Porsche 914 for years and I like something that's a little quirky and unusual. I was really methodical about selecting a 201, and have a spreadsheet filled with details on every M20J I found on the market in the last few months, organized by a scale of 1-3: "1" planes were exactly what I was looking for, "2" planes would do if I couldn't find a suitable "1" plane, and "3" planes you probably couldn't pay me to take. I did pricing workups on most and ended up with analyses of varying levels of 68 aircraft in all. N201XG was one of 8 aircraft I took a really close look at, and after spending a lot of time with remarkably patient and helpful selling broker, I bought the plane and moved it from its last base in Texas to its current home in Seattle. It turns out that N201XG spent 16 years in the Puget Sound area, from 1983 through 1999. Some of the maintenance logs show entries from Galvin Flying, the local flight school (and MSC before they got out of the repair business) where I met my insurance minimums in a rental M20J, N161MP. After that, N201XG spent 17 years in new England and 2 in Texas. This plane has a recently overhauled engine with the Firewall Forward 225hp STC, which was previously installed in the plane in 1987, then removed in 1999, before being reinstalled in 2017. It's an amazing plane and I've had a blast on local flights. I'm looking forward to expanding my radius as the weather warms and I work through the small list of remaining minor maintenance issues. Feels pretty neat to have an aircraft that has such a long history in my neighborhood.
  20. I'm stumped and could use a hand with my IO-360 in my 1978 M20J. I'm collecting small particles in my fuel servo strainer. Occasionally some sneaks through and clogs up a fuel injector -- in the process of diagnosing this, it's clogged injectors over a half-dozen times. The particles are small and mostly ferrous, and only collect in the servo. The gascolator screen is completely clean. A few things we've eliminated. Whenever my mechanic cleans the injectors and screen, he runs gallons of fuel through the boost pump and it all comes out clean. Happens with a brand new Weldon boost pump. (The 17-year-old Dukes gave up halfway through troubleshooting.) Definitely not the injectors; those are too far downstream and we replaced them anyway since the screens were shot. The engine has ~50 hours on it and the mechanical fuel pump, servo, and flow divider are all overhauled. They could be a problem as we haven't changed them out yet. Has anyone seen anything like this? First photo is the initial pile of junk we removed from the fuel servo screen. Mostly ferrous. Second photo is the next pile we removed after 0.5-1.0 hours on the engine. Same material.
  21. adverseyaw

    Crud in my fuel servo strainer

    I'm curious as well to know which one that is :-) I pulled the Dukes pump out last week and installed a Weldon. No filter in the pump head but I think my mechanic pulled the screen nearby.
  22. adverseyaw

    Crud in my fuel servo strainer

    It was overhauled this time last year and has 50 hours on it since then, not sure its age before that. Talking with my mechanic and engine builder, we're thinking the fuel pump is the most likely culprit. These are great ideas -- it seems like the screens upstream of the servo all have larger openings. The servo screen is the finest one and seems to catch the sandy particles from further up. (My mechanic also mentioned they look a lot like blasting media.) No doubt. I've only seen one or two flakes come out of the fuel drains in the last month or two but my A&P will be clearing the finger strainers in the tanks and will see if there's anything in there. Yep, it's got the Dukes filter. We haven't seen anything in there so far, although the holes in the screen are a lot bigger than the fine screen in the servo (which is where everything is getting stuck.) Thanks all above, this is helping us nail this down. An update based on what we've found and things we've tried: The servo inlet filter crud may be sand or blasting media. It may be coming from the mechanical fuel pump. The junk in the injectors is coming from the servo or flow divider, OR it's coming up further upstream (the fuel pump) and the servo inlet screen is getting clogged enough that the bypass spring is letting it through. Unfortunately the extent of clogging so far means that once we identify and clear the source, we're going to have to disassemble and clean the mechanical pump, servo, and flow divider.
  23. adverseyaw

    Crud in my fuel servo strainer

    These are all great ideas... a few things we've checked in response: Fuel hoses are the new brown silicone ones Fuel cap flanges seem to be OK, and so far the particles don't look like rust Current theory we're evaluating is that we have some residual particles being caught in the servo screen, but the particles in the injector are coming from either the servo or the flow divider. (Of those, servo is much more likely candidate. Not much in the flow divider to go wrong.) Thanks all so far
  24. adverseyaw

    Crud in my fuel servo strainer

    Some of it stuck to a magnet, but not all of it. That's on my list but given that we've dumped 20 gallons through it already (and the boost pump runs a gallon or two clean after every cleaning), I don't have my hopes up. :-(
  25. adverseyaw

    Mooney down in Washington

    I recently met Don over email when he offered to help me build instrument time as I work toward my rating. We were just scheduling over the weekend. He was so enthusiastic about helping out. Such a tragedy to hear. I'm familiar with the hillside. It's prominent on the approach to BLI. Rest well, Don.