Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

912ul miss

Matronics Email Lists Forum Index -> RotaxEngines-List

View previous topic :: View next topic

Author Message

egp8111

Joined: 25 Mar 2010
Posts: 49

Posted: Mon Jun 18, 2012 6:23 am Post subject: 912ul miss

I know this issue has been worked over a few times on the forum but I cant seem to find anything that matches my situation.  Here's the deal,  the 912 starts fine after warm up on the initial mag check it has about a 150-200 rpm drop on either mag at 4000 rpm.  In flight it has an occasional miss at 5000rpm, some more notable than others.  It also runs rough between 3000 and 4000 rpm not missing just rough feeling.  After I land I can check the mags again and they only have a drop of about 50 rpm on either side.  I've pneumatically balanced the carbs and they are dead on at 2500 rpm. The carbs have been cleaned and adjusted.  new plugs etc.  Also today I flew through a very light rain shower and the engine began to run notably rough at 5000rpm.  After I left the area of rain it cleared up.  Carb ice ?  I do not have the carb heat box installed.   

Any ideas?

Thanks EG

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

Blumax008(at)aol.com
Guest

Posted: Mon Jun 18, 2012 6:29 am Post subject: 912ul miss

Possible leads. Tie it down or chock it good in a dark hangar at night  and see if you see any fireworks are visible from the spark plug  leads. May be breaking down at higher rpms or causing occasional trouble. Just a  guess.

  

  In a message dated 6/18/2012 10:24:54 A.M. Eastern Daylight Time,  egp8111(at)aol.com writes:

  	  Quote: 	
		  -->    RotaxEngines-List message posted by: "egp8111"    <egp8111(at)aol.com>



I know this issue has been worked over a few    times on the forum but I cant seem to find anything that matches my    situation.  Here's the deal,  the 912 starts fine after warm up on    the initial mag check it has about a 150-200 rpm drop on either mag at 4000    rpm.  In flight it has an occasional miss at 5000rpm, some more notable    than others.  It also runs rough between 3000 and 4000 rpm not missing    just rough feeling.  After I land I can check the mags again and they    only have a drop of about 50 rpm on either side.  I've pneumatically    balanced the carbs and they are dead on at 2500 rpm. The carbs have been    cleaned and adjusted.  new plugs etc.  Also today I flew through a    very light rain shower and the engine began to run notably rough at    5000rpm.  After I left the area of rain it cleared up.  Carb ice    ?  I do not have the carb heat box installed.   

Any    ideas?

Thanks EG





Read this topic online    here:



http://forums.matronics.com/viewtopic.php?p=375987#375987

	


 [quote][b]

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Mon Jun 18, 2012 12:07 pm Post subject: Re: 912ul miss

Hi EGP,



What are the plugs gapped at? They should be between .023 - .027. The wider gap for the hotter months. If the gap is too narrow especially in the summer you will get bigger mag drops and possible roughness.

The second item is 2500 rpm is too low to do a very good balance. I know it's in the book, but the book could have a few changes done in a few areas. If you balance at 2500 and then run the rpm up to 4000 you will find that they will be off again. 2500 is too close to the idle circuit range and just doesn't flow enough fuel/air to get set up well. Check the plug gaps, apply the thermal conducting paste and not anti seize and then re-balance the carbs at 3500-4000. I would bet your engine will run even smoother. Depending on how your air cleaner is set up you may have taken on a little water, but no big deal as it usually runs through the system especially with 91 oct with ethanol.

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

Display posts from previous:

	Matronics Email Lists Forum Index -> RotaxEngines-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum