Page 2 of 3 FirstFirst 123 LastLast
Results 41 to 80 of 84

Thread: New (to me) Supercub... Running hot? Charging issues too

  1. #41

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    I like the ideas. They will have to wait till next week. Flying the jet now.. not near as fun, but pays a hell of a lot better.

    I'll get after it. I'll get it all figured out. It was probably just under 15.. and not consistent. At times it would show 12.1 or so. When it was showing 15.. I could trip off the field current, and it was slowly drawing down towards 12.


    JP

  2. #42

    Join Date
    Sep 2003
    Location
    Vermont
    Posts
    190
    Post Thanks / Like
    My typical auto store 2/10/55 charger on the 2A setting takes my fully charged PC680 from 13.02 to 15.5V in 15 seconds. The label on my PC680 says 14.8 max. AGMs should be on Tenders.
    What's a go-around?

  3. #43

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    Mechanic reported that he thought the #2 intake has been leaking since new. (40 hours, 8 years) I hope that was the source of some of my temp issues. As I said.. leaning it at cruise yielded no increase in RPM before it dropped off. It's fixed now. Got my 6.00s on (for the skis) and the new battery is in.

    I'll get to test it on Tuesday.

    He did say that the carb was a carb for a 160hp.. so he didn't think drilling the jet would be necessary. He didn't get to some of the baffle sealing I wanted to do.. but I'll do that when it's in the heated shop for ski install.

    JP

  4. #44

    Join Date
    Jan 2007
    Posts
    1,382
    Post Thanks / Like
    If you still have problems Check the mag timing (did you figure out what mags you have) and pull the carb to look at the jet. Just because the carb fits does not mean that it has the proper jet.
    DENNY

  5. #45

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    I did speak to him about timing. I didn't remember to ask him about it (I'm in Kansas, he's in Maine)

    We'll see what next week brings. My plan is to fly the hell out of it, do an oil change with analysis. See where I'm at.

    JP

  6. #46

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like

    exhaust

    As an aside..

    Not sure if you'd call this the seaplane lip. Unlike some others I've seen.. my exhaust comes out in this outlet, and not forward like some.

    JPIMG_2430.JPGIMG_2427.jpg

  7. #47

    Join Date
    May 2014
    Posts
    446
    Post Thanks / Like
    JP

    I you are seeing cyl temps north of 450 please don’t “fly the hell out it” until you have addressed hi temp issues.

    lots if discussion on this issue in the past, quick summary:

    1) check that engine is operating correctly,
    no intake leaks, timing is correct etc.
    check accuracy of your probes
    2) baffling, often overlooked but critical.
    place a light source by firewall and look thru cowl inlets, (in a dark hangar helps)
    you should see NO light, little leaks add up.
    I recently replaced poor fitting felt baffling with well fitting silicone material
    and dropped #3 CHT 30 deg at cruise.
    3) carb, mixture leaning authority - at least 150 deg EGT sea level at 2300 rpm, more if you are in really cold country.
    theres no “160 hp” carb, just a 150 carb that may not be delivering enough fuel. (Hope your mechanic is not the same guy that missed the leaves between your cylinders during pre-buy )

    Other things that that can help - sea plane lip, bigger cowl doors etc.. lots of work for minimal return.
    hope these and previous suggestions help, good luck.

  8. #48
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    Exhaust valves not completely closing can cause high CHT & EGT temperatures.
    N1PA

  9. #49

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    I was under 450 on a cold day.. I guess i'm making the assumption that the lean condition was caused by the number two intake pipe being loose. I'll find out when I get home and can fly it.

    New battery installed.

    I think in looking at other's pictures, and using my recollection only...

    My baffling was in contact with the aft lower portion of the #3 cylinder fins. It seems from others that this area should be 'stood off' and have some space between that low corner of the cylinder and the baffling.

    I wasn't getting any rise out of the rpm while leaning in cruise. Until that issue is fixed, you're right.. I won't be flying it a bunch. I hope we've gotten the bulk of the issue. I do have plans to do some better air sealing when it's in the shop for ski install.

    Thanks.. I'll follow up once i get to fly it.

    JP

  10. #50
    Scouter's Avatar
    Join Date
    Nov 2003
    Location
    Exeter Maine
    Posts
    1,779
    Post Thanks / Like
    Your in good hands with those Twitchell boys. Good old fashioned Mainers, they still do business on handshakes. They will get to the bottom of it

    when you get it flying let's hook up and fly. You can get mixed up with the rest of the pack that runs around here. You will never be the same

    jim
    Likes RaisedByWolves liked this post

  11. #51

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    Jim.

    Thanks. I've been banging around here a while. Started at 3b5 over 30 years ago... when I was 14.

    I went off to aviation college.. taught at twitchells when I was still in school. With graduation coming up.. Mike just told me.. You graduate this spring, right? When I said yeah.. He said.. good, you're gonna go fly for Roger Currier. That's how small town works.

    I never did a pre buy. The plane was right at my home airport. I'm still a little nervous about how little it flew... but I hope we've got the major issue addressed.. and a few tweaks are still to come. We'll see. This stuff is a journey.. not a one and done. Looking forward to getting my skis in a couple weeks. I'll spend my time doing tweaks while it's in the heat.

    JP

  12. #52
    stewartb's Avatar
    Join Date
    Oct 2012
    Location
    Alaska
    Posts
    3,769
    Post Thanks / Like
    I wouldn’t expect an RPM rise from leaning in cruise. I pay little attention to RPM when leaning through idle cutoff. What’s important is leaning authority in level cruise with a warm engine. If you can’t demonstrate a 150* EGT rise between full rich and peak you’re running too lean. Especially as temps get cold and air gets dense. You need more fuel flow for cold weather ops. If you’re lean your engine will get hot on climbout and probably will never recover to normal temps during cruise. If you were lean in summer temps, be very careful in colder temps. Don’t get too caught up in talk about jet size. Your carb is simple and the main jet is the simplist part. It’s just a brass pipe. If you need more fuel? Ream it a little larger. If that isn’t enough? Ream it a little more. You’re experimental so you don’t even have to keep quiet about doing it.

    An intake leak at #2 doesn’t explain high temps at #3. Fix the baffle at #3 to allow air to flow down the aft side.

    None of this stuff is hard. It should be fun. Get in there and get your own hands dirty. Dial that plane in and enjoy it.
    Last edited by stewartb; 12-08-2018 at 11:07 AM.

  13. #53

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    Thanks stewart. Yeah.. The leaf or two I got wasn't helping. I saw a little piece sticking out in the corner.. then found them once i got on a ladder.

    Even with that.. I think the baffling around number 3 isn't 'right' for this engine in this plane. I'll try to get a good picture before I start messing with it.

    The EGTs were quite high.. I'm hopeful that they ALL were because of the really bad leak at 2. I guess we'll find out. Thanks for the tip on leaning. I'm in line with your thinking. I'd rather have the fuel available.. then lean with the mixture.. than want more and not able to get it!

    I'm working through an intercom issue. Since Im at work.. I'm reduced to using a few pictures I took of cockpit.. zooming in to find model numbers, then looking up manuals online. I have a few ideas for hopeful quick fixes via settings, then changes to wiring. doing all I can with internet research. Stinks to not have a heated hangar.



    JP

  14. #54
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    Quote Originally Posted by JP11 View Post
    The EGTs were quite high.. I'm hopeful that they ALL were because of the really bad leak at 2.
    That leak at #2 only addresses #2. And you should get a rise in rpm at cruise when you lean the mixture.
    N1PA

  15. #55
    Gordon Misch's Avatar
    Join Date
    Dec 2003
    Location
    Toledo, Wa (KTDO)
    Posts
    3,083
    Post Thanks / Like
    Leaning in cruise gives me about 20 or so RPM increase. 160 HP, and the carb is unchanged from when it was on my 150 HP.
    Gordon

    N4328M KTDO
    My SPOT: tinyurl.com/N4328M (case sensitive)

  16. #56

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    I got a chance to fly it yesterday. The simple stuff.

    I found the baffling behind 3 still needs work. I was able to get it away from touching at the corner.
    3 is still the hottest. In a climb to about 2k.. at 50kts or less, I was seeing CHT around 460. Cruising around 3 was just over 4.. Others 350.

    I'm still suspect of EGTs in general. They always read 1300+ . I was able to lean at cruise and get about a 100 increase

    Oil temps were stable about 120 to 140.

    Voltage was consistently in the 14 to 15 range. (plan to turn down the regulator a bit)

    Mechanic forgot to check the timing. That's the last suspect at the moment. I think they are slicks.

    I'm going to do some baffle sealing in a couple weeks when it's inside for the ski install.

    I got to test my aux tanks. Seems it moved most all the fuel (I've got 24s for main, and 10 aux each side.. not sure how many long trips I'd want to use them)


    JP

  17. #57

    Join Date
    Jan 2007
    Posts
    1,382
    Post Thanks / Like
    I would recommend you stop doing hard climb outs. At least until you get the temp issue cleared up. Clean the cowling hinge and put aluminum duct tape over the hinge. Sounds like you are on the right track and I suspect things will get better. If your slick mags need a overhaul (new SB out) I would trash them and get a set of Bendix.
    DENNY

  18. #58
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    What charging system do you have? And how are you monitoring voltage? I.e. voltmeter in panel or handheld?

    Web
    Life's tough . . . wear a cup.

  19. #59
    Gordon Misch's Avatar
    Join Date
    Dec 2003
    Location
    Toledo, Wa (KTDO)
    Posts
    3,083
    Post Thanks / Like
    CHT gauge(s) and probe(s) calibrated together? Dunno whether those probes are thermocouples or thermistors, however there could potentially be a mismatch. If thermocouples, if I recall correctly I think all of the wiring connection pairs need to be at the same temperature (i.e. same location). At least I think mis-calibration should be ruled out.
    Gordon

    N4328M KTDO
    My SPOT: tinyurl.com/N4328M (case sensitive)

  20. #60
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    Thermistors reduce their resistance when heated. That's what varies the reading on the gauge. I've never seen them on CHT's or EGT's.

    Thermocouples actually produce a current flow in response to being heated. Works great and extremely accurate. Unfortunately there are two types of probes used on general aviation systems. K type and J type. Doesn't really matter what the difference is for us except when replacing probes. You need to match the wire colors of the probes removed. J type will be a red wire and a white wire and the K type will be a yellow wire and a red wire. I don't care what the parts store tells you, DO NOT wire up probes of a different color than what was installed by the manufacturer. They are not interchangeable. As a common sense item, just install probes provided by the manufacturer and you'll be safe. A quick visual will show you if someone installed a wrong probe. Just look for the odd one out of the bunch. And while you're in there check that each EGT probe is installed at the same distance from the exhaust flange. There is not exact distance called out but there will be a range of minimum to maximum. They need to be installed within this range and all at the same distance. CHT probes can be two different types. One is installed in a well in in the cylinder head and the other goes under the spark plug just like a spark plug gasket. Check and see if you have one probe that is of the opposite type than the rest. For best accuracy they should be all of the same style.

    As has been mentioned, if you want to check for one odd probe, put them all in an oil bath and heat it slowly. Use an accurate thermometer to monitor the oil temp and watch the gauge. If all probes match the rise in heat, you're good. If one is off, then it's time to troubleshoot. Swap probe positions on the harness and see if the odd temp follows the probe or stays in the same position on the gauge. If you have and older system, check if the wire length is critical. With some older systems, you were not allowed to cut any wires to probes. If you cut them to length for installation, then it would disrupt the calibration of the gauge. All of the newer systems allow you to cut wires to length as long as it's not the thermocouple wires themselves.

    Web
    Life's tough . . . wear a cup.
    Thanks Gordon Misch, CamTom12 thanked for this post
    Likes Gordon Misch, mike mcs repair liked this post

  21. #61

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    Quote Originally Posted by wireweinie View Post
    What charging system do you have? And how are you monitoring voltage? I.e. voltmeter in panel or handheld?

    Web
    It's an alternator. I'm not sure which brand. Voltmeter in the panel.

  22. #62
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    Find a brand/model on the alternator & reg. and it will help with troubleshooting. Alternator doesn't narrow it down much.

    Assuming a digital voltmeter?

    Web
    Life's tough . . . wear a cup.

  23. #63

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    Quote Originally Posted by wireweinie View Post
    Find a brand/model on the alternator & reg. and it will help with troubleshooting. Alternator doesn't narrow it down much.

    Assuming a digital voltmeter?

    Web
    No, it's an analog gauge. I'll get a name off the alternator tomorrow. Thanks. Supposed to be -2 in the morning. I sure won't be flying it! Ordered my insulated covers and reiff heater today.

    JP

  24. #64
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    Before you adjust the voltage, verify bus voltage with a digital voltmeter. Then, if adjustment is needed, set it while monitoring voltage with the digital unit. Analog is NOT accurate enough for this.

    Web
    Life's tough . . . wear a cup.
    Likes mike mcs repair liked this post

  25. #65

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    Thanks. Digital multi-meter it will be then.
    Likes mike mcs repair liked this post

  26. #66
    stewartb's Avatar
    Join Date
    Oct 2012
    Location
    Alaska
    Posts
    3,769
    Post Thanks / Like
    Did you ever say what type of battery you have? I use B&C alternators and regulators in both planes. With the Odyssey the voltage is 14.4 99% of the time. It shows 14.5 the other 1%. With the EarthX I see 14.1. My batteries seem to be happy in both cases.

    What engine monitor are you using? Just curious. In my engine monitor experience I haven’t had probe accuracy problems. Connections? Yes, but that’s all or nothing. Testing probes on old analog temp gauges was common. I don’t know anyone who does it with digital instruments. Swap a probe to validate, maybe, but that’s it.

    1300-ish EGTs sound normal. The only CHT that’s high is #3. It looks like you’re getting it straightened out.
    Last edited by stewartb; 12-13-2018 at 07:00 AM.

  27. #67

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    It's an odyssey. New one now.

    Engine gauges are non powered. has a rotary switch with 1 thru 4 for each gauge. CHT and EGT

    JP

  28. #68
    stewartb's Avatar
    Join Date
    Oct 2012
    Location
    Alaska
    Posts
    3,769
    Post Thanks / Like
    You’d probably be a lot happier with digital.
    Likes wireweinie liked this post

  29. #69

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    You’d probably be a lot happier with digital.
    I agree. Looks like 7 or 800 for a single gauge that would do all of what 4 gauges are doing now. It's on 'the list' but it's down a ways. I'm thinking Pmags is higher priority. Skis, Reiff are bought and going on in a couple weeks. After that.. I'll see where I'm at. Woke up to 0 degrees. Will take my dad for his first ride today when it warms up.. a bunch!

    JP

  30. #70
    stewartb's Avatar
    Join Date
    Oct 2012
    Location
    Alaska
    Posts
    3,769
    Post Thanks / Like
    Pmags are pretty cool. I love how they're timed!

    Enjoy the cold air performance but watch the cold air mixture until you get this thing sorted out. You do have a CO detecter, right?

  31. #71

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    I had to go look it up..
    Likes hman442, mike mcs repair liked this post

  32. #72

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    OK.. some answers.

    Analog gauge for voltage isn't worth much. What looks like 15+ is really right on 14.5

    This came down shortly after start. However.. while monkeying around with it.. (loading up with lights and such) I routinely saw just 11.5V. I could shut off the field current with the left half of the master, and it would slowly come down on voltage.

    I guess I was surprised that 1500rpm was not holding steady voltage at 12+ . It seemed sporadic as to if it was charging or not.. load or not. At times it would go back to 13+ . but the behavior wasn't predictable. I took pictures of the components. I'm guessing that the voltage regulator is incorporated into the alternator? When the cowl is off, I can get some better images. I'll share some other stuff in a different post. Thanks Much

    IMG_2466.JPGIMG_2467.JPGIMG_2472.JPGIMG_2471.JPG

  33. #73

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    As for temps. I made it a point to fly out faster. 60 to 70kts. This kept #3 down into the 450 to 460 range at full power. This was yielding right at 2500rpm.

    Cruising around.. 1, 2 and 4 were all in the 350 area. 3 stayed around 395 to 405

    EGT are suspect. Most of them are in the 1300 to 1400 range. #3 was 1500 to pegged 1600+... however.. when messing with the selector switch, I would occasionally see it bouncing around in the 1300 to 1400 range... not steady, literally bouncing.

    As for mags... I got a close up picture. Hard to read the tag. However... what I could see said made in Sidney NY.. which makes them bendix I believe.

    On the plus side.. Gave dad a ride for the first time in it. Saw a bald eagle just taking off in a field. I could tell it had a real big wingspan. I turned around to see where it was headed, and it had perched in a tree top, along with a second one. Cool sighting.

    JP

  34. #74
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    Your charging system is failing. Could be as simple as needing brushes but I suspect the regulator. Voltage should be much, much more stable. Right after startup it's common to see the voltage a few tenths of a volt lower than normal. This is because the alternator is trying to recharge the battery along with running anything else that happens to be turned on. Otherwise you should see 14.2 volts, +/- .2 volts. That's ideal. Anytime you see 12 volts or less, you are running on battery only and your alternator is not working. Have you checked for good connections on the alternator? Do you have a brand/model?

    Web
    Life's tough . . . wear a cup.

  35. #75

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    No brand/model I can see currently. If I have to pull the lower cowl... I might just as well pull it for rebuild. Happen to have a local pilot that owns a shop. Last time I went in to get the snowcat alternator checked.. by the time we were done BS'ing.. He handed it back to me. I asked.. Is it good? He says.. It is now.. I rebuilt it, didn't even bother to test it.

    Thanks.

    With the realization I have Bendix mags.. My priorities I think have shifted from going to Pmags to getting a EDM350 engine display.

    JP
    Likes stewartb liked this post

  36. #76
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    [QUOTE=JP11;734240With the realization I have Bendix mags.. My priorities I think have shifted from going to Pmags to getting a EDM350 engine display.

    JP[/QUOTE]
    When you check the mag timing, if it is off have the mags pulled and get the Egap checked and corrected. It's a quick job.
    N1PA
    Likes DENNY liked this post

  37. #77
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    Ask them to do a 500 hr inspection on the mags.

    Web
    Life's tough . . . wear a cup.

  38. #78

    Join Date
    Oct 2018
    Posts
    37
    Post Thanks / Like
    I think the charging system gave up today. After start, it showed the 14.5

    That didn't last long.. and before half an hour it was down into just over 12.. which means it was really 11.5

    They are going to pull the alternator when I'm gone next week.

    JP

  39. #79

    Join Date
    Jul 2010
    Location
    Elizabeth, WV
    Posts
    454
    Post Thanks / Like
    Quote Originally Posted by wireweinie View Post
    Ask them to do a 500 hr inspection on the mags.

    Web
    Oh my, yes. Your problems are nagging me to think that your aircraft spent a lot of time in the "if it ain't broke, don't fix it mode". I think you may have significant preventive maintenance items to catch up on. I like to avoid magneto failures that result from no maintenance.
    You can't get there from here. You have to go over yonder and start from there.

  40. #80
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    What's the history of this setup, firewall/forward? You said in the first post that there's about 40 hours on this build? If so, what is the history of the engine? Used engine on a new built airframe? Overhauled engine? How about the mags, alternator, exhaust system, oil cooler, etc? All new or used?

    If you need to replace the alternator, I highly recommend the Plane-Power stuff. Also make sure to replace the wire harness if changing out that old charging system. It's not much more effort than cobbing the old wires onto a new system and it eliminates any problems with old/crap wires.

    Web
    Life's tough . . . wear a cup.

Similar Threads

  1. Replies: 3
    Last Post: 02-01-2018, 11:40 AM
  2. I'm charging 15 amps.
    By NimpoCub in forum Super Cub Sick Bay
    Replies: 17
    Last Post: 07-22-2007, 01:29 AM
  3. SuperCub Running Rich
    By PA-18 in forum Super Cub Sick Bay
    Replies: 0
    Last Post: 11-22-2002, 10:48 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •