VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #21  
Old 04-27-2018, 04:07 PM
scottmillhouse's Avatar
scottmillhouse scottmillhouse is offline
 
Join Date: Apr 2007
Location: Madison, AL
Posts: 228
Default

We may have fixed our problem too. Disconnected all black box connectors, inspected all wiring, cleaned up grounds and reassembled and it works. Smooth pulling over 5100 static. Flying it another day with heavy gusty cross winds today.
__________________
Scott- 2018 dues paid
Got medical back, now building a 7A; N579RV reserved, new engine installed, doing FWF, instruments & finish painting.
RV-12 #120515, N319RV 1st flight 12/2015 now over 270 hours.
RV-9A, 536 hours sold, RV-7 sold, Kitfox sold
Reply With Quote
  #22  
Old 05-01-2018, 10:29 AM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 927
Default

Well, I'm pretty sure that I have found my problem as well. First, a few more details.

After reading everything that i could find on the subject, all things pointed to the cards, and that included suggestions from Rotax gurus. I ordered the small carb kits from Lockwood, and when they arrived, I went to work. By the way, like many things, the scary part of the job was the unknown. After watching a few videos, and reading up on the process, I set up a very clean area with lots of light an a magnifying glass. It was really pretty straight forward, and to be honest, I didn't find the smoking gun. There was a little black residue hear and there which cleaned off nicely. Oh, I guess the choke works a bit smoother now.

After re-installing the carbs and doing a run up, the roughness was still there on Ignition A, and with all of the black plugs, I was still unable to identify the bad cylinder. So much for carbs being the problem. Everything that I read stated that ignition component failure is very rare, but I thoroughly did a physical inspection again of all ignition connections. I tugged on every connector, seated every plug, and verified that there were no broken or chafed parts.

So, I ran it up again and had the same roughness but this time I kept it up at about 3600 rpm, putting up with the roughness for a couple of minutes and the did a radical shutdown. This time I could detect that cylinder 1 plugs were worse. .On a whim, and really not expecting anything good to come of it, I dig out the old plugs, picked the best looking two and put them in cylinder 1.

Wow! It was like magic! So I did the carb balance and everything looks good. Bottom line, I guess I had replaced a bad spark plug with a fresh out of the box bad spark plug. Thanks for everyone's help. ..........Tom
__________________
2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
Reply With Quote
  #23  
Old 05-01-2018, 03:15 PM
scottmillhouse's Avatar
scottmillhouse scottmillhouse is offline
 
Join Date: Apr 2007
Location: Madison, AL
Posts: 228
Default

So it was ignition after all. Glad you sorted that out. We will do some plug swapping ourselves just to make sure.

I kind of high jacked your thread with our issue. Today flew the plane. Mag drop only 50 with A off but about 200 with B off at initial run up. Flew for about 45 minutes. Engine smooth and strong. Next run up with B off drop was about 350 with noted roughness but it did fly and run strong and smooth. Still thinking perhaps the 1T, 2T coil may be bad and missfiring. It is very compact and inaccessible under the black boxes. Is there an easy way to check coils still on the engine?
__________________
Scott- 2018 dues paid
Got medical back, now building a 7A; N579RV reserved, new engine installed, doing FWF, instruments & finish painting.
RV-12 #120515, N319RV 1st flight 12/2015 now over 270 hours.
RV-9A, 536 hours sold, RV-7 sold, Kitfox sold
Reply With Quote
  #24  
Old 05-01-2018, 06:07 PM
alexe alexe is offline
 
Join Date: May 2013
Location: Temecula, CA
Posts: 247
Default

Scott,
Swap the coils by plugging them into the opposite ignition module. See if trouble stays or follows the swap. That should tell you if its the coil pack or the ignition module.
Alex
__________________
Alex Erdelyi
RV-12 #120758, N912AE
Flying as of 4/28/15
Paid through December, 2018
Reply With Quote
  #25  
Old 05-02-2018, 05:39 AM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 927
Default

Hey Scott. Coils and ignition modules are pretty solid devices. In fact my search did not truly identify any failures, although I am sure there have been some. For less than $3 each, and the most simple swap, spark plugs are a definite go to item. I know that I sure have learned my lesson. Good luck with your fix.....Tom
__________________
2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
Reply With Quote
  #26  
Old 05-02-2018, 07:43 PM
Jolly Jolly is offline
 
Join Date: Nov 2016
Location: San Francisco, CA
Posts: 45
Default

For hard to find issues like this a good 1,2,3,4 step diagnostics makes things easier and usually cheaper because most issues aren't some exotic problem. Jumping around usually takes much longer to find an issue. There are usually simple solutions and common causes to learn from others. Replacing plugs is a good start for a larger than normal mag drop. Then trimming back the spark plug wire ends by 3/8" that go into the threaded prong plug cap. Poor grounds or wire wire rubbed through that goes under something on top of the engine is another good place to check. If you drop on plug then that is around 300 rpm mag drop. To be an ignition module that would be 800-1000 drop and it may just stop the engine. Ignition CDI modules rarely go bad for the 26 degree BTDC normal running phase. Where they do go bad at times is on the start circuit at either 4 degrees BTDC older modules or the soft start at 3 degrees ATDC. The soft start module seem to be holding pretty well. The failures seem to be more of the older CDI modules.
Reply With Quote
  #27  
Old 05-03-2018, 10:16 AM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 927
Default

Quote:
Originally Posted by Jolly View Post
For hard to find issues like this a good 1,2,3,4 step diagnostics makes things easier and usually cheaper because most issues aren't some exotic problem. Jumping around usually takes much longer to find an issue. There are usually simple solutions and common causes to learn from others. Replacing plugs is a good start for a larger than normal mag drop. Then trimming back the spark plug wire ends by 3/8" that go into the threaded prong plug cap. Poor grounds or wire wire rubbed through that goes under something on top of the engine is another good place to check. If you drop on plug then that is around 300 rpm mag drop. To be an ignition module that would be 800-1000 drop and it may just stop the engine. Ignition CDI modules rarely go bad for the 26 degree BTDC normal running phase. Where they do go bad at times is on the start circuit at either 4 degrees BTDC older modules or the soft start at 3 degrees ATDC. The soft start module seem to be holding pretty well. The failures seem to be more of the older CDI modules.
Thanks Jolly. All good stuff. I almost called you during my late frustration period. It just seemed like nothing that I did helped. Traditional diagnostic strategies just don't seem to work on Rotax, such as reading spark plugs. By the time you get to them, they are all black, at least cylinders 1 and 2. I think that doing the radical shutdown gave me a little more insight, but maybe I just got lucky. I will keep the mag drop numbers that you posted. Like I said Good Stuff. I have the add-on soft start module. Not sure how they fail, when they do. My guess is that it will either kill an ignition, or fail to retard. Not sure and it is good to know that they are pretty stable devices. Thanks a bunch. ......Tom
__________________
2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
Reply With Quote
  #28  
Old 05-03-2018, 10:41 AM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 927
Default

Hey Jolly!!

Any experience with trigger coil, or ignition coil failures. Such as reliability of them, and perhaps mag drop clues like you did with the spark plug and ignition module clues.

Thanks..Tom
__________________
2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
Reply With Quote
  #29  
Old 05-03-2018, 02:47 PM
scottmillhouse's Avatar
scottmillhouse scottmillhouse is offline
 
Join Date: Apr 2007
Location: Madison, AL
Posts: 228
Default

All ignition problems fixed. The last problem with excess mag drop was a "bad" new out of the box spark plug. Makes you wonder about the supply of new NGK Rotax plugs with two cases at the same time. Just swapped back in two of the old 70 hour plugs to 1 and 2 top and all now works like it should. There were other issues earlier like corroded ground connections that caused the earlier serious ignition loss.
__________________
Scott- 2018 dues paid
Got medical back, now building a 7A; N579RV reserved, new engine installed, doing FWF, instruments & finish painting.
RV-12 #120515, N319RV 1st flight 12/2015 now over 270 hours.
RV-9A, 536 hours sold, RV-7 sold, Kitfox sold
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 09:05 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.