 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
jon(at)joncroke.com
Guest
|
 Posted: Sun Jun 04, 2006 6:49 pm Post subject: 912 Rough running on either left or right mag -- smooth on b |
 |
|
Would anyone have an idea on the following problem:
I get about a 400 rpm drop and a definite roughness (like a cylinder
missing) when performing a mag check... identical reaction for left AND
right... but when using both mags the engine seems to run just fine and run
smooth... I still get full power and have been flying... but this behavior
conerns me... didnt use to be this way... Rotax manual calls for a max 300
rpm drop..
Using a 80hp 912
Thanks for any suggestions...
| | - 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 |
|
|
|
| Back to top |
|
 |
jon(at)joncroke.com
Guest
|
| Posted: Mon Jun 05, 2006 7:33 pm Post subject: 912 Rough running on either left or right mag -- smooth on b |
|
|
D,
I think you're on the right track... I balanced the carbs today, no difference.......changed the spark plugs... no diff... and then redid the plug wire boots... no change. Since I have no EGT gauges, I cannot verify your idea on my engine... BUT, I will have a friend, tomorrow, that can move the choke lever, at the carb, one carb at a time -- and see if that smooths out the engine. I know the choke works only when at idle, so that is where I will check. I am guessing that (based on your analysis) I have a carb that is leaned out because of dirt in a jet... so something similar.. but which one?! Also, maybe a heat gun aimed at the exhaust of each cylinder will show me if one side of the engine is running lean... NOW I know why some people have EGT gauges on their engine! (s o much for that altitude compensating Bing!)
THanks for your ideas! Will let you know what fixes this thing.
Jon
Hello Jon -
We experienced large ign drops (> 650 RPM) and EGT problems
on our 914. Turns out our mixture (as delivered from the
factory) was too lean. After setting both carb needles one
notch richer everything operated within spec.
We're hot/humid down here (Texas), and the Rotax expert we
talked to mentioned that the nominal carb needle (mixture)
settings would need to be set per the prevailing weather in
your location. Perhaps you're teetering on the edge between
one mixture setting and another?
Note that the Rotax purists will probably scold you (using
an Austrian accent!) for saying left or right. We have a
top (A) and a bottom (B) ignition module... regardless of
what the key switch says. 
D
I get about a 400 rpm drop and a definite roughness (like a cylinder
missing) when performing a mag check... identical reaction for left AND
right... but when using both mags the engine seems to run just fine and run
smooth... I still get full power and have been flying... but this behavior
conerns me... didnt use to be this way... Rotax manual calls for a max 300
rpm drop..
Using a 80hp 912
Thanks for any suggestions...
| | - 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 |
|
|
|
| Back to top |
|
|
|
|
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
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
