YS 110FZ very lean at Mid throttle, help!
04-20-2008, 12:54 PM
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YS 110FZ very lean at Mid throttle, help!
Hi All,
Went to the weekend Aerobatics comp in Southern Scotland and my YS110 decided to have a bad day...after the 1st flight where the engine stopped on climb-out and broke the spinner (but the prop and nuts stayed attached).I got the YS guys at the comp to have a look but nobody could understand it. Basically i have good tank pressure ok, and set-up is :- fuel 20% heli fuel. Prop APC14x12. Hyde Nose ringless soft mount. ( New Os F type plug) Tettra non-bladdered tank.
When opening the throttle the engine picks up speed rapidly (and is very lean) around mid throttle and then seems only slightly lean
at the top end. Unscrewing the main needle half a turn out or in half a turn (whilst running at full power) makes no difference to the engine setting whatsoever.
We stopped the engine, richend the needle up to two turns from closed and then screwed the regulator 1/4 turn in....(makes pump work harder) Engine still lean
at mid throttle and then engine goes slobbering rich and stops at the throttle top end.
We unscrewed the regulator 1/2 turn .So it is now 1/4 turn ccw from 1st flight and now engine just does the same thing.
Any ideas...?
I have to say with the bad weather we have had in the UK i have not used the motor for two months but i drained the tank after the last flight and the engine is not gummed up and started readily for the 1st flight of the day.
I have never stripped the engine before but it was a 2nd hand buy from a clubmate who had not flown it.
thanks for your ideas
Dave
Went to the weekend Aerobatics comp in Southern Scotland and my YS110 decided to have a bad day...after the 1st flight where the engine stopped on climb-out and broke the spinner (but the prop and nuts stayed attached).I got the YS guys at the comp to have a look but nobody could understand it. Basically i have good tank pressure ok, and set-up is :- fuel 20% heli fuel. Prop APC14x12. Hyde Nose ringless soft mount. ( New Os F type plug) Tettra non-bladdered tank.
When opening the throttle the engine picks up speed rapidly (and is very lean) around mid throttle and then seems only slightly lean
at the top end. Unscrewing the main needle half a turn out or in half a turn (whilst running at full power) makes no difference to the engine setting whatsoever.
We stopped the engine, richend the needle up to two turns from closed and then screwed the regulator 1/4 turn in....(makes pump work harder) Engine still lean
at mid throttle and then engine goes slobbering rich and stops at the throttle top end.
We unscrewed the regulator 1/2 turn .So it is now 1/4 turn ccw from 1st flight and now engine just does the same thing.
Any ideas...?
I have to say with the bad weather we have had in the UK i have not used the motor for two months but i drained the tank after the last flight and the engine is not gummed up and started readily for the 1st flight of the day.
I have never stripped the engine before but it was a 2nd hand buy from a clubmate who had not flown it.
thanks for your ideas
Dave
04-20-2008, 01:19 PM
#2
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RE: YS 110FZ very lean at Mid throttle, help!
Sounds like the regulator is too lean. Richen it (CCW) Dialing the regulator IN is leaning it and will make things worse. The regulator does not pump fuel. It just regulates as the name implies. The pressure at which it opens to allow fuel that is already under pressure int he tank is force fed to the engine. The regulator controls how much flows. Adjusting the tension on the spring and plunger just sets what pressure and for how long the plunger stays open. So dialing the screw in means more pressure...and the this makes the plunger stay closed longer before....and leans the mixture. Reducing the tension on the screw means it opens sooner and allows more flow. This is richer setting. There is not work being performed by the regulator its just a control valve. The work is being being done when the down stroke of the piston pushes air back through the check valve and pressurizes the tank. Once the tank is under pressure the regulator just opens or closes the gate.
It might also have some dirt or debris blocking one of the passages.This would restrict flow. I suggest removing the HS need and cleaning the seat out and also flushing the regulator parts out.
Troy Newman
Team YS
It might also have some dirt or debris blocking one of the passages.This would restrict flow. I suggest removing the HS need and cleaning the seat out and also flushing the regulator parts out.
Troy Newman
Team YS
04-20-2008, 04:50 PM
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RE: YS 110FZ very lean at Mid throttle, help!
Dave,
Sorry to hear about your problem.
I think you were very courageous even attempting to fly given the strength of the wind at Dumfries over the weekend. Scotland the Brave!
If you follow this link - http://www.gbrcaa.org/acrobatfiles/Y...%20Systems.pdf - from the Home Page on the GBR/CAA Web Site, it will take you to an article explaining the operation of the fuel control systems on YS engines, including your YS110.
Most people believe that screwing the regulator in will make the engine run richer, but as Troy says, the reverse is the case on those YS engines that pressurise the tank (i.e 53's, 63's, 90's, 110's and the 140 Sports and 140 L's.) The reason why this is so is explained in the article. Basically it boils down to the difference between a 3-chamber pressure regulator as used in these models of YS engines, and the more common 2-chamber regulator as employed for example in Perry Pumps.
To make matters even more confusing, the regulator in the Dingo series of YS engines - 140, 160 and 170 - works in the more conventional sense i.e. turning the brass screw inwards (CW) will make the mixture richer.
If your refer to the sketches and supporting text in the article, all will be revealed.
Regards
Bob
Sorry to hear about your problem.
I think you were very courageous even attempting to fly given the strength of the wind at Dumfries over the weekend. Scotland the Brave!
If you follow this link - http://www.gbrcaa.org/acrobatfiles/Y...%20Systems.pdf - from the Home Page on the GBR/CAA Web Site, it will take you to an article explaining the operation of the fuel control systems on YS engines, including your YS110.
Most people believe that screwing the regulator in will make the engine run richer, but as Troy says, the reverse is the case on those YS engines that pressurise the tank (i.e 53's, 63's, 90's, 110's and the 140 Sports and 140 L's.) The reason why this is so is explained in the article. Basically it boils down to the difference between a 3-chamber pressure regulator as used in these models of YS engines, and the more common 2-chamber regulator as employed for example in Perry Pumps.
To make matters even more confusing, the regulator in the Dingo series of YS engines - 140, 160 and 170 - works in the more conventional sense i.e. turning the brass screw inwards (CW) will make the mixture richer.
If your refer to the sketches and supporting text in the article, all will be revealed.
Regards
Bob
04-21-2008, 02:12 PM
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RE: YS 110FZ very lean at Mid throttle, help!
Troy and Bob,
Thank you very much for taking the time to write back.
I have not had time to work on the engine but the information you gave me is invaluable and the gbrcaa link with pictures "Says a thousand words!", I hope to get more time later in the week to have a good look at the engine.
Bob,
I think you were very courageous even attempting to fly given the strength of the wind at Dumfries over the weekend. Scotland the Brave!
Either brave or very, very stupid!!!!
Most people believe that screwing the regulator in will make the engine run richer, but as Troy says, the reverse is the case on those YS engines that pressurise the tank (i.e 53's, 63's, 90's, 110's and the 140 Sports and 140 L's.)
That explains everything! the guy who helped me, flies Dingo's so that explains the problems we were having!!!
It is only my 2nd Comp for proper! and my previously tested 2m model (flown 3 times beforehand), the last comp i had an rudder DS8401 servo output arm strip ((leaving me with 1/2 r/h rudder!!!,The problem was the Hangar 9 turn-around pull-pull wheel did not have the servo splines machined all the way round the circumferance so stripped the servo output shaft as it let go!)(what a wierd failure, eh?)), the Rx switch disintegrated on the model and the engine (YS140L) quit inverted on flight 2 whilst doing a downwind slow roll!!
I need some luck at this game i really do...3rd time/comp lucky!!!!
Regards
Dave
Thank you very much for taking the time to write back.
I have not had time to work on the engine but the information you gave me is invaluable and the gbrcaa link with pictures "Says a thousand words!", I hope to get more time later in the week to have a good look at the engine.
Bob,
I think you were very courageous even attempting to fly given the strength of the wind at Dumfries over the weekend. Scotland the Brave!
Either brave or very, very stupid!!!!
Most people believe that screwing the regulator in will make the engine run richer, but as Troy says, the reverse is the case on those YS engines that pressurise the tank (i.e 53's, 63's, 90's, 110's and the 140 Sports and 140 L's.)
That explains everything! the guy who helped me, flies Dingo's so that explains the problems we were having!!!
It is only my 2nd Comp for proper! and my previously tested 2m model (flown 3 times beforehand), the last comp i had an rudder DS8401 servo output arm strip ((leaving me with 1/2 r/h rudder!!!,The problem was the Hangar 9 turn-around pull-pull wheel did not have the servo splines machined all the way round the circumferance so stripped the servo output shaft as it let go!)(what a wierd failure, eh?)), the Rx switch disintegrated on the model and the engine (YS140L) quit inverted on flight 2 whilst doing a downwind slow roll!!
I need some luck at this game i really do...3rd time/comp lucky!!!!
Regards
Dave
04-25-2008, 07:37 AM
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RE: YS 110FZ very lean at Mid throttle, help!
I don't know that I can explain your problem exactly, but here are two suggestions. If you have already checked all these things then I apologise.
1) if this problem came on suddenly, then you may have some goop somewhere creating a ball cock effect in the fuel path, typically in the needle valve. Have you got the fuel filter in place the right way around, and is it clean?
2) if the problem came on slowly then it might be due to wear on the needle valve needle and seat especially if you tend to leave fuel in the engine at the end of the day. Also having a needle valve extension can do this by causing extra vibration. If I need to extend the needle valve, I use a short piece of bowden cable.
Lastly if there is any air leak around the rocker cover or pushrod ends, it can do funny things. My 140 used to do this a lot. Run fine on the ground and die lean about 10 ft off the ground on takeoff. If it wasn't the plug it was the !"£% rocker cover again.
1) if this problem came on suddenly, then you may have some goop somewhere creating a ball cock effect in the fuel path, typically in the needle valve. Have you got the fuel filter in place the right way around, and is it clean?
2) if the problem came on slowly then it might be due to wear on the needle valve needle and seat especially if you tend to leave fuel in the engine at the end of the day. Also having a needle valve extension can do this by causing extra vibration. If I need to extend the needle valve, I use a short piece of bowden cable.
Lastly if there is any air leak around the rocker cover or pushrod ends, it can do funny things. My 140 used to do this a lot. Run fine on the ground and die lean about 10 ft off the ground on takeoff. If it wasn't the plug it was the !"£% rocker cover again.
04-25-2008, 07:40 AM
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RE: YS 110FZ very lean at Mid throttle, help!
Nearly forgot. It is pretty rare for a non return valve to malfunction, but it can and would produce the symptoms you describe.
04-25-2008, 07:51 AM
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RE: YS 110FZ very lean at Mid throttle, help!
The regulator adjust the mid range, close the regulator 1/8 of a turn at a time and try it again, remember to go full power before you recheck to stabilize tank pressure with the new setting.
04-25-2008, 02:23 PM
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RE: YS 110FZ very lean at Mid throttle, help!
Hi Troy,Bob,DJM and Apereira,
Well i took the regulator off the motor cleaned the diaphram, valve and valve seat, crankcase metering hole and replaced the assembly then cleaned the main needle valve.
This afternoon between rain showers i got out and ran the motor...
I started with the needle 1.75 turns open and the regulator screw flush with the screw slot running down the crankshaft centreline...Same symptoms..so i opened the regulator counterclockwise 1/4 turn and things improved. Another 1/4 turn and it was much better. I now have control of the main needle mixture at full power also and the exhaust was nice and smokey. (I am using 20% Heli Fuel) The engine really starting to pick up about 3/4 - 7/8 full power on the TX ..much more linear than before where the motor was peaking at about 1/2 throttle.. Unfortunately the weather closed in so i packed up without flying it, before i got drowned!
I think the engine is cured..I still need to fly it to be certain as the other problem i had with the previous settings was the engine would refuse to accelerate cleanly after a few minutes flying (i.e on exiting a vertical downline to horizontal flight the engine would go to die when the throttle was opened and took gentle opening and coaxing the throttle to full power)..But i think i have made progress.
I am amazed at just how much control over the engine at mid range power settings the regulator screw has.
Thank you all for your ideas and experience without it i was lost..I hope my third competition goes much more smoothly now!!
best wishes and high scores
David
Well i took the regulator off the motor cleaned the diaphram, valve and valve seat, crankcase metering hole and replaced the assembly then cleaned the main needle valve.
This afternoon between rain showers i got out and ran the motor...
I started with the needle 1.75 turns open and the regulator screw flush with the screw slot running down the crankshaft centreline...Same symptoms..so i opened the regulator counterclockwise 1/4 turn and things improved. Another 1/4 turn and it was much better. I now have control of the main needle mixture at full power also and the exhaust was nice and smokey. (I am using 20% Heli Fuel) The engine really starting to pick up about 3/4 - 7/8 full power on the TX ..much more linear than before where the motor was peaking at about 1/2 throttle.. Unfortunately the weather closed in so i packed up without flying it, before i got drowned!
I think the engine is cured..I still need to fly it to be certain as the other problem i had with the previous settings was the engine would refuse to accelerate cleanly after a few minutes flying (i.e on exiting a vertical downline to horizontal flight the engine would go to die when the throttle was opened and took gentle opening and coaxing the throttle to full power)..But i think i have made progress.
I am amazed at just how much control over the engine at mid range power settings the regulator screw has.
Thank you all for your ideas and experience without it i was lost..I hope my third competition goes much more smoothly now!!
best wishes and high scores
David
04-25-2008, 03:38 PM
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RE: YS 110FZ very lean at Mid throttle, help!
David,
Delighted to hear you have had some success. I think you will find that richening the regulator (by screwing it out!) should also solve your problem of opening up cleanly after a long downline. However if not, send me an E-Mail and I’ll provide you with my telephone number so that we can try to sort things out over the ‘phone.
I’m pleased that you are sticking with it and not giving up despite your early setbacks. F3A can be a very frustrating game at times but I know that you will get great support from your colleagues up in Scotland. The ultimate rewards will be well worth it.
Very best wishes for your next competition. Let me know how you get on.
Regards
Bob
Delighted to hear you have had some success. I think you will find that richening the regulator (by screwing it out!) should also solve your problem of opening up cleanly after a long downline. However if not, send me an E-Mail and I’ll provide you with my telephone number so that we can try to sort things out over the ‘phone.
I’m pleased that you are sticking with it and not giving up despite your early setbacks. F3A can be a very frustrating game at times but I know that you will get great support from your colleagues up in Scotland. The ultimate rewards will be well worth it.
Very best wishes for your next competition. Let me know how you get on.
Regards
Bob
