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Engine quits at full throttle

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rlborger(at)mac.com
Guest

Posted: Fri Sep 04, 2009 1:35 pm Post subject: Engine quits at full throttle

Fellow Europaphiles:



I'm at 10.5 hrs on my XS Monowheel.  (Just getting the hang of landing  

it on pavement)  As you can see from the signature block it has a  

Rotax 914 and Airmaster C/S prop.  On the last flight the engine  

developed a surge and a miss at full throttle at about 500' on  

takeoff.  When I retarded the throttle and surge stopped and miss went  

away.   After immediate RTB, pulled the upper cowl and began an  

inspection.  1st thing noticed was that it was not really obtaining  

full throttle.  Only about 37.5 in MP.  Full throttle is 39 in MP and   

37 - 38 in MP is in the unstable range for the turbo controller.  That  

explained the surging.  Located the reason the throttle wasn't going  

to max and fixed it.  Also checked both fuel filters.  Secondary was  

fine.  Main was had considerable crud so it was replaced.   I can now  

get full throttle.  Re-synched the carbs.  Runs nice and smooth.



Now here's what happened today on a full-power, chocks-in, tail tied  

down, run-up test.



Engine starts immediately.  I kept the idle at 2000 - 2100 RPM to warm  

up.

Engine warmed up, all temps and pressures in the green.  Prop  

controller set Auto and T/O.  Main and Boost pumps are both on,

Advance throttle.  Everything is OK up to engine RPM 5790 & MP 36 in.

When the throttle is advanced beyond 37.5 in MP the engine quits.   

Like fuel starved or ignition cuts out.  It just quits.

Retard throttle back below 37.5 in MP and it re-starts and runs  

smoothly.

Throttled back to 4000 RPM and did a "mag" check.  Left-Off drop is  

about 275 RPM, Right-Off drop is 305 - 310 RPM.

Throttle back to idle and shut off ignition, the engine stops and  

after about 15 seconds there was a large backfire through the exhaust  

(first time for that!).

Engine has only run on 100LL with appropriate amounts of Decalin TCP &  

Marvel Mystery Oil to help with the lead situation.  Oil is still nice  

and clear.



Do any of you Rotax Gurus have a suggestion as to why the engine cuts  

out when full throttle is applied?  Any suggestion for things to check  

and/or fix?



Thanks in advance for your help,

Bob Borger

Europa Kit #A221 N914XL, XS Mono, Intercooled 914, Airmaster C/S

http://www.europaowners.org/N914XL

Aircraft Flying!

3705 Lynchburg Dr.

Corinth, TX  76208

Home:  940-497-2123

Cel:  817-992-1117

craigb(at)onthenet.com.au
Guest

Posted: Sat Sep 05, 2009 5:14 am Post subject: Engine quits at full throttle

Not that I am a rotax expert, but from my car tuning and racing experience,

I would suggest

that either your pump/s are not able to keep up with demand from the carbs

(unlikely, given

you are running two), you have and open return line??? (you did put the

restrictor in the return line

AFTER the carbs), or your carbs are WAY WAY TOO lean and you simply don't

have enough fuel entering

the engine to keep it running at full throttle. This is the most likely

situation IMHO assuming you have

the restrictor installed. An excessively lean mix could also account for the

lack of MP at full throttle.

No fuel to burn means no expanding gasses so no pressure to drive the

impeller side of the turbo, so less

boost than expected so a lower MP than expected.



You can get some good automotive lean/rich gauges for around $100 these day,

if you lift the needles in your carbs

a bit and it runs better, I would suggest you invest in one to get your mix

right. Failing that, you mentioned contaminated

fuel filter, have you checked to see if the fuel is leaving the tank freely,

by dropping the fuel line off the carb

and see how much fuel comes out when the pumps are on.



hope this helps



craig



kit 577

vh-xsv



_

mau11(at)free.fr
Guest

Posted: Sat Sep 05, 2009 6:45 am Post subject: Engine quits at full throttle

hI all,

 is anyone know a solution for  resolve the ignition shield to stop engine on the 912?

  

 Thanks

  

  

    

 mau11

 2009-09-05



   

 En réponse au message

de  : craig bastin

 du :  2009-09-05 15:18:05

 À :  europa-list(at)matronics.com

 CC : 

 Sujet : RE: Europa-List:  Engine quits at full throttle

  

  --  > Europa-List message posted by: "craig bastin"   <craigb(at)onthenet.com.au >

  

 Not that I am a rotax expert, but from my car tuning and racing experience,

 I would suggest

 that either your pump/s are not able to keep up with demand from the carbs

 (unlikely, given

 you are running two), you have and open return line??? (you did put the

 restrictor in the return line

 AFTER the carbs), or your carbs are WAY WAY TOO lean and you simply don't

 have enough fuel entering

 the engine to keep it running at full throttle. This is the most likely

 situation IMHO assuming you have

 the restrictor installed. An excessively lean mix could also account for the

 lack of MP at full throttle.

 No fuel to burn means no expanding gasses so no pressure to drive the

 impeller side of the turbo, so less

 boost than expected so a lower MP than expected.

  

 You can get some good automotive lean/rich gauges for around $100 these day,

 if you lift the needles in your carbs

 a bit and it runs better, I would suggest you invest in one to get your mix

 right. Failing that, you mentioned contaminated

 fuel filter, have you checked to see if the fuel is leaving the tank freely,

 by dropping the fuel line off the carb

 and see how much fuel comes out when the pumps are on.

  

 hope this helps

  

 craig

  

 kit 577

 vh-xsv

  

 _

  

  

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rampil

Joined: 04 May 2007
Posts: 870

Posted: Sat Sep 05, 2009 8:11 am Post subject: Re: Engine quits at full throttle

Hey Bob,



Similar story on my flight tests.  Check for soot on bottom of your

carbs. On mine, one of the exhaust pipes would come lose at full throttle only, and just enough to boil the fuel in one float bowl!



Good Luck,



Ira

_________________
Ira N224XS

rlborger(at)mac.com
Guest

Posted: Sat Sep 05, 2009 8:48 am Post subject: Engine quits at full throttle

Ira,



Thanks.  I'm going to run more checks tomorrow.  I'll check for the  

loose exhaust.



Best regards,

Bob Borger

Europa Kit #A221 N914XL, XS Mono, Intercooled 914, Airmaster C/S

http://www.europaowners.org/N914XL

Aircraft Flying!

3705 Lynchburg Dr.

Corinth, TX  76208

Home:  940-497-2123

Cel:  817-992-1117



On Sep 5, 2009, at 11:11, rampil wrote:



 	  Quote: 	
		   



 Hey Bob,



 Similar story on my flight tests.  Check for soot on bottom of your

 carbs. On mine, one of the exhaust pipes would come lose at full  

 throttle only, and just enough to boil the fuel in one float bowl!



 Good Luck,



 Ira



 --------

 Ira N224XS

budyerly(at)msn.com
Guest

Posted: Sat Sep 05, 2009 11:35 am Post subject: Engine quits at full throttle

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Bob,

  

 Sorry to hear about your engine woes.

 From my experience in the shop here are some things I've run into:

  

 Check that there is not 912S restrictor in your return line for the  914.  The restrictor is necessary in the 912S but Rotax forbids it in the  914.  Make sure the return is not pinched either.  See your  install manual on line with Rotax.

  

 Don't make the mistake of swapping the fuel intake line and return  lines.  (Believe it or not the engine runs, but goofs up the fuel metering  as one would expect, and won't accelerate properly or hit top end.)

  

 I hate to admit that I have seen one fuel pump hooked up backwards  electrically, and due to plumbing wouldn't feed enough fuel for full power, but  it would start...

  

 Check your airbox and static pressure sensors aren't clogged or  kinked, or worse yet still plugged.  

  

 The new 914s have the removable fuel pans, and easy access to the float  bowls.  Pull them and check for crap.

 If dirty, get a rebuild kit and clean up the carbs.

  

  Since you have 10 hours on your engine,  it may be a mute point by now  but fuel quality is a combination of the source and materials quality in the  plane...  Fuel lines are not shipped clean and there is residue in them as  well as the tank.  Fuel with ethanol will clean better than Av gas.

  

 FBO's do filter their gas to a very high standard, but I find very  fine white organic material in it that my filters found, so think about pre  filtering your fuel.  Since doing so I've had no problems.

  



 My technique for assuring clean fuel tank and lines:

 First.  Get a pre filter funnel for your fuel. Fill the tank to  the neck with 20 gallons of premium unleaded with ethanol.  Shake  the aircraft and check for leaks. 

  

 Next, disconnect the fuel delivery line at the engine fuel regulator and  pump the fuel back into the cans, alternating between main and reserve  sides.  The filters will clean the tank.  The pre tank filter funnel  will clean the fuel going back in.  Fill again, and allow to sit.   More will settle, so repeat the fuel straining.  Then I do it one more time  (total of three times) to insure tank and more importantly the lines are  clean.  Fuel lines are notorious about being dirty.  I don't use the  filtering gas for my first engine run, I Premium gas or Av gas. 

  

 While doing the above, do a flow and pressure check.  I have a valve  hooked to the line off the aircraft fuel line with a T and fuel pressure gauge  to check for fuel delivery pressure and and volume.  It is also a good time  to adjust the fuel flow measuring sensors.  If you have in and out  metering, hook the delivery line to the return line and circulate the  fuel.  Fuel flow should read zero.  (912S owners can do this with one  fuel flow device and the restrictor installed and measure the flow rate and  pressure delivery with fuel returning to the tank.)  

  

 Bud Yerly

 Custom Flight Creations

  

  

 



 



   [quote][b]

rsementi(at)gmail.com
Guest

Posted: Sat Sep 05, 2009 11:27 pm Post subject: Engine quits at full throttle

Always nice to hear your wisdom Bud!



Thanks,RS

On Sep 5, 2009, at 3:28 PM, "Bud Yerly" <budyerly(at)msn.com (budyerly(at)msn.com)> wrote:



[quote] <?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Bob,

  

 Sorry to hear about your engine woes.

 From my experience in the shop here are some things I've run into:

  

 Check that there is not 912S restrictor in your return line for the  914.  The restrictor is necessary in the 912S but Rotax forbids it in the  914.  Make sure the return is not pinched either.  See your  install manual on line with Rotax.

  

 Don't make the mistake of swapping the fuel intake line and return  lines.  (Believe it or not the engine runs, but goofs up the fuel metering  as one would expect, and won't accelerate properly or hit top end.)

  

 I hate to admit that I have seen one fuel pump hooked up backwards  electrically, and due to plumbing wouldn't feed enough fuel for full power, but  it would start...

  

 Check your airbox and static pressure sensors aren't clogged or  kinked, or worse yet still plugged.  

  

 The new 914s have the removable fuel pans, and easy access to the float  bowls.  Pull them and check for crap.

 If dirty, get a rebuild kit and clean up the carbs.

  

  Since you have 10 hours on your engine,  it may be a mute point by now  but fuel quality is a combination of the source and materials quality in the  plane...  Fuel lines are not shipped clean and there is residue in them as  well as the tank.  Fuel with ethanol will clean better than Av gas.

  

 FBO's do filter their gas to a very high standard, but I find very  fine white organic material in it that my filters found, so think about pre  filtering your fuel.  Since doing so I've had no problems.

  



 My technique for assuring clean fuel tank and lines:

 First.  Get a pre filter funnel for your fuel. Fill the tank to  the neck with 20 gallons of premium unleaded with ethanol.  Shake  the aircraft and check for leaks. 

  

 Next, disconnect the fuel delivery line at the engine fuel regulator and  pump the fuel back into the cans, alternating between main and reserve  sides.  The filters will clean the tank.  The pre tank filter funnel  will clean the fuel going back in.  Fill again, and allow to sit.   More will settle, so repeat the fuel straining.  Then I do it one more time  (total of three times) to insure tank and more importantly the lines are  clean.  Fuel lines are notorious about being dirty.  I don't use the  filtering gas for my first engine run, I Premium gas or Av gas. 

  

 While doing the above, do a flow and pressure check.  I have a valve  hooked to the line off the aircraft fuel line with a T and fuel pressure gauge  to check for fuel delivery pressure and and volume.  It is also a good time  to adjust the fuel flow measuring sensors.  If you have in and out  metering, hook the delivery line to the return line and circulate the  fuel.  Fuel flow should read zero.  (912S owners can do this with one  fuel flow device and the restrictor installed and measure the flow rate and  pressure delivery with fuel returning to the tank.)  

  

 Bud Yerly

 Custom Flight Creations

  

  

 



 



    	  Quote: 	
		  

	


[b]

acrojim7534(at)YAHOO.COM
Guest

Posted: Sun Sep 06, 2009 3:51 am Post subject: Engine quits at full throttle

Bob

 

On the full power check, with the plane tied down you stated that at 5790 RPM you had 36 inches MP. Then you stated when you advanced the throttle to past 37.5 inches MP the engine quit... What was the RPM at 37.5 inches MP ? Did the engine RPM exceed 5800 RPM ? to reach the 37.5 Inches MP ?

 

At 5800 RPM you should be seeing 39 to 40 inches MP.

 

When you installed the Airmaster prop, did you set the high RPM "stop" in the hub to limit RPM to 5800.???  In order to get full boost of the turbo you must have the throttle wide open, with the RPM's being goverened by the prop hub.  This can only be done by setting the prop pitch to limit the max RPM to 5800.

 

If you did not, the Airmaster installation manual tells you how to do this. It must be done for proper operation of the engine. And also to prevent overspeed of the engine on takeoff....

 

Jim Brown



--- On Fri, 9/4/09, Robert Borger <rlborger(at)mac.com> wrote:

From: Robert Borger <rlborger(at)mac.com>

Subject: Engine quits at full throttle

To: europa-list(at)matronics.com

Date: Friday, September 4, 2009, 9:29 PM




Fellow Europaphiles:



I'm at 10.5 hrs on my XS Monowheel.  (Just getting the hang of landing it on pavement)  As you can see from the signature block it has a Rotax 914 and Airmaster C/S prop.  On the last flight the engine developed a surge and a miss at full throttle at about 500' on takeoff.  When I retarded the throttle and surge stopped and miss went away.   After immediate RTB, pulled the upper cowl and began an inspection.  1st thing noticed was that it was not really obtaining full throttle.  Only about 37.5 in MP.  Full throttle is 39 in MP and  37 - 38 in MP is in the unstable range for the turbo controller.  That explained the surging.  Located the reason the throttle wasn't going to max and fixed it.  Also checked both fuel filters.  Secondary was fine.  Main was had considerable crud so it was replaced.   I can now get full throttle.  Re-synched the carbs.  Runs nice and smooth.



Now here's what happened today on a full-power, chocks-in, tail tied down, run-up test.



Engine starts immediately.  I kept the idle at 2000 - 2100 RPM to warm up

h&jeuropa

Joined: 07 Nov 2006
Posts: 650

Posted: Sun Sep 06, 2009 6:29 am Post subject: Re: Engine quits at full throttle

Bob,



Did you try hooking up a computer to the TCU and using the TLR program so see what the TCU is seeing?  There is the monitor portion of the software and also a history portion that collects some historical data.  That might point you to the problem.  Helped us a couple of weeks ago.



Jim & Heather

david.stanbridge(at)swift
Guest

Posted: Sun Sep 06, 2009 10:52 am Post subject: Engine quits at full throttle

I had exactly the same problem this weekend with the rpm cycling

between 4500 and 4800 on a 914 fitted with a Airmaster propeller. The

probem was found to be the sealing of the carburettor sumps to the

main body. After diassembling these to see if there was any crud at

the bottom, which there was not, and putting them together the issues

disappeared.



Hope this is of some help.



Dave Stanbridge

rlborger(at)mac.com
Guest

Posted: Sun Sep 06, 2009 12:11 pm Post subject: Engine quits at full throttle

Fellow Europaphiles,



Update as of this morning, 2009 09 06.



Over the last two days, I have checked all the areas recommended by  

you folks.  Lots of good ideas!  Thanks to those who took the time to  

call.  I appreciate all the help.



Everything checks out so far without tearing down the carbs.  I've  

reached the point where I need a better check of the airbox/fuel  

differential pressure.  It could very well be that there was  

insufficient fuel pressure at full boost to over come that level of  

boost.  The UMA gage and sender I have installed seem to be binary,  

either 0 or 1.  And that's not right.  It should read between 2 and 5  

PSI.  Tomorrow I'll be evaluating why the differential pressure isn't  

reading properly.



I have completed six full power run-ups.  Three yesterday and three  

today.  The engine performed perfectly at all times.



Engine started before three blades went by.  Maintained idle in the  

2000 - 2100 RPM to warm up.

Once the engine warmed up and all temperatures were in the normal  

operating range I confirmed that the prop was in Auto and T/O.

Advanced the throttle slowly, watching RPM and MP.

At full throttle the engine was turning 5750 RPM and 39 in MP.  Fuel  

flow was 8.1 to 8.2 GPH (roughly 32 L/H for you folks in Europe).   

Right on the chart numbers.

The engine was very smooth, no surging, no missing, no hesitations, no  

sign of stopping.

I held it at full throttle for about 30 seconds and then brought it  

back gently to idle.  Allowed it to idle for a minute or so before the  

next run to full power.

Yesterday and today, the final full power run was held for a full  

minute.

After the final run, the throttle was gently returned to idle (1900  

RPM) and the engine allowed to idle for at least 1 minute to allow the  

turbo to cool down.

And the engine was shut down with the Ignition switches.



Tomorrow I will be looking at the differential pressure gage package  

to see what's wrong with it.  The 914 really needs an accurate  

differential pressure indication.



I'll keep you posted,

Bob Borger

Europa Kit #A221 N914XL, XS Mono, Intercooled 914, Airmaster C/S

http://www.europaowners.org/N914XL

Aircraft Flying!

3705 Lynchburg Dr.

Corinth, TX  76208

Home:  940-497-2123

Cel:  817-992-1117



On Sep 4, 2009, at 16:29, Robert Borger wrote:



 	  Quote: 	
		   



 Fellow Europaphiles:



 I'm at 10.5 hrs on my XS Monowheel.  (Just getting the hang of  

 landing it on pavement)  As you can see from the signature block it  

 has a Rotax 914 and Airmaster C/S prop.  On the last flight the  

 engine developed a surge and a miss at full throttle at about 500'  

 on takeoff.  When I retarded the throttle and surge stopped and miss  

 went away.   After immediate RTB, pulled the upper cowl and began an  

 inspection.  1st thing noticed was that it was not really obtaining  

 full throttle.  Only about 37.5 in MP.  Full throttle is 39 in MP  

 and  37 - 38 in MP is in the unstable range for the turbo  

 controller.  That explained the surging.  Located the reason the  

 throttle wasn't going to max and fixed it.  Also checked both fuel  

 filters.  Secondary was fine.  Main was had considerable crud so it  

 was replaced.   I can now get full throttle.  Re-synched the carbs.   

 Runs nice and smooth.



 Now here's what happened today on a full-power, chocks-in, tail tied  

 down, run-up test.



 Engine starts immediately.  I kept the idle at 2000 - 2100 RPM to  

 warm up.

 Engine warmed up, all temps and pressures in the green.  Prop  

 controller set Auto and T/O.  Main and Boost pumps are both on,

 Advance throttle.  Everything is OK up to engine RPM 5790 & MP 36 in.

 When the throttle is advanced beyond 37.5 in MP the engine quits.   

 Like fuel starved or ignition cuts out.  It just quits.

 Retard throttle back below 37.5 in MP and it re-starts and runs  

 smoothly.

 Throttled back to 4000 RPM and did a "mag" check.  Left-Off drop is  

 about 275 RPM, Right-Off drop is 305 - 310 RPM.

 Throttle back to idle and shut off ignition, the engine stops and  

 after about 15 seconds there was a large backfire through the  

 exhaust (first time for that!).

 Engine has only run on 100LL with appropriate amounts of Decalin TCP  

 & Marvel Mystery Oil to help with the lead situation.  Oil is still  

 nice and clear.



 Do any of you Rotax Gurus have a suggestion as to why the engine  

 cuts out when full throttle is applied?  Any suggestion for things  

 to check and/or fix?



 Thanks in advance for your help,

 Bob Borger

 Europa Kit #A221 N914XL, XS Mono, Intercooled 914, Airmaster C/S

 http://www.europaowners.org/N914XL

 Aircraft Flying!

 3705 Lynchburg Dr.

 Corinth, TX  76208

 Home:  940-497-2123

 Cel:  817-992-1117

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