grcourtney

My Feedback: (1)

put a glow plug in it..if it runs look at the spark plug (cracking, carbon, plug cap for snug fit, plug gap)

gary

bjr_93tz

Thanks Gary, I have an OS F glow plug sitting around that I will give a go. The engine responds well to ground adjustments of the regulator and high speed needle but after 2-3 minutes in the air it starts to cough and sputter then drop back to idle and won't respond to throttle. sometimes it stops other times it just keeps ticking over.

Land it, hit it with the starter, and it fires right up and runs like a Swiss watch. Maybe the CDI is overheating, the glowplug test will sort that out?

On the very odd occasion I've fired it up and the engine has stopped after a few seconds of idle, a quick check reveals it's not pumping any fuel. It's the second prod of the starter that doesn't even give me a "pop" that let's me know the pump isn't pumping in this case but this is rare. I think Amram got his hands on a new pump from YS earlier in the thread I wonder how that went for him?

All up I love the motor when it works but when it spits the dummy it puts a very expensive airplane at risk. You wouldn't care if it's in an ugly stick but practicing deadstick landings with your best F3A plane isn't what I signed up for....

Dave Harmon

Have you checked the CDI battery? When the battery gets low it will miss badly.
Probably not the problem if powered by the receiver battery.
Considering it runs ok for several minutes then goes bad....might be worth a check.

Oh....what does 'spit the dummy mean'?
hehehe

lodomjr

My Feedback: (6)

A bad spark plug will cause you to chase the mixture all around. I know this from experience with the same symptoms you were having. We put the mixer back where it was running strong and put the glow plug back in it and it ran fine. We did have to richen the top end up just a little.

Larry

bjr_93tz

Hi Dave, When I switched to 2.4, I ran the CDI out of the RX through a filter and it worked fine, I have since switched back to a big 'ol lumpy 4 cell ni-cd to isolate power supply issues. I have also switched the RX back to a even bigger lumpy ni-cd pack in case I was getting low voltage failsafe's (throttle set to idle). Both are are now running off seperate big lumpy ni-cad's and engine problems haven't changed.

"spit the dummy" refers to the practice of some infants who are throwing a tantrum to "spit out" the dummy/pacifier that you shove in their mouth to try and shut them up. I think that holding a pillow over their face after you put in the dummy might help..

Larry, I've swapped spark plugs but my "spare" was a used one that had been working fine. I have to buy a new one to isolate that. Maybe both my plugs have gone bad? I've used up all my spare gaskets and o-rings, I'd love to have a spare cdi and pump to change out but with the Nationals tommorrow I've really run out of time.

If it is just a spark plug I'll kick myself so hard, if it's a pump or CDI I'm gonna write an e-mail to YS as this is the second comp I've missed because of engine problems (the first was rear bearing failure replaced under warranty, but still missed a comp). I'm really over making changes, driving out to the flying field and still having the same problem as it only quits in the air. It runs like a swiss watch on the ground so shed testing is useless.

When I get it sorted in a few weeks after the Holidays I'll reply back.

Thanks
Brett

Dave Harmon

Hahahaha......okokokok.....I get it now!

You might check the plug gap....anything over .015" and it will start to have that rich sounding miss....much larger might cause rougher running.
Also, my engine runs better if I gap the plug to .009".
If you are using that Chinese plug....note that at the top of the threads just under the hex....the diameter is much larger than the inside of the washer which will cause the washer to go off center far enough to cause a leak. Put some alky in the plug chamber and roll it over to see if it is leaking.....this caused me a LOT of problems.

bjr_93tz

Thanks for the reply Dave, "Genuine" YS plugs but you raised an interesting point. I have noticed some wetness in the bellypan and sparkplug cap/lead and have been blaming it on the o-rings on the intake pipe, and/or valve cover gasket hence using up my stocks of o-rings and gaskets to little positive effect.

I'll double check this as well. Thanks

Just a quick update, a fellow competitor at the Nats advised me that he too has had a rear bearing failure as well as pump problems requiring steel inserts in the pump valve seat area to sort it out.

Following this I have now faced the pump surfaces to remove any visible signs of wear, polished the teflon plunger faces and stretched the pump springs by 0.5mm. My pump also has one stiff spring and one soft one? I'll rip out for a flight this afternoon and take a glow plug with me just in case.

NJRCFLYER2

My Feedback: (42)

It would be worth a careful check of the condition of the spark plug cap and wiring. Unless well secured to avoid any rotation of the plug cap as the engine rocks on the mount, you will get wear that can hurt the plug as well as the plug cap.

Another tip Ilearned from other more experienced CDI drivers is that the Hall sensor wire can break in the area where it leaves the housing, again due to rocking around. It may cause intermittent problems.

Going back to glow just to make sure everything else is good is a great idea. It greatly simplifies the trouble shooting.

bjr_93tz

Thanks Ed, I just poped back to update on this afternoons fun and another trip out to the field and this time I didn't even bother to take off.

It didn't prime properly by rocking it back and forth which was a bad sign right from the start. It would fire up then stop, fire up then stop. Eventually it fired up and ran ok for a while while I fine tuned the needle however it stopped after a prolonged idle and you could see bubbles in the injector line and all the rocking in the world wouldn't move them, in fact they traveled backwards towards the pump??

Cut a long story short the pump isn't doing what it's supposed to do in fact by sucking on the discharge side of the pump I was ablle to draw lots of bubbles and the only place ar can get in is via the crankcase past the pump plunger.

The engine is 3 weeks past warranty but I still written to YS to express my disapointment and ask for their advise on the matter.

Not wanting to sound like a total pratt but I am the State Champion in my class and it's not very often the Nationals are 100km down the road. It's wrecked my whole holidays (Christmas/New year) trying to sort this mess out. This is the 2nd comp out of 4 I've missed because of this engine. It'll run like a train for months then decide to crack up 2-3 weeks out from a comp.

Getting the thing to run properly when everything is working ok is easy, it's fault finding the thing when something decides to not work properly is the hard bit if you haven't got the spares on hand to change every part one at a time....

topiwala

Hey,
Your problem sounds exactly like what I had with my brand new 170 cdi. Thats come back from YS - repaired and 100% working. The prblem was that the engine would not prime, rocking back and forth or cranking over at full throttle. When I manually forced fuel to the injector, and got it to ignite, it would stop due to starvation. There was air travelling back towards the pump - in the wrong direction!!...same as what you've described.
anyway, the returned engine seems to have a new pump diaphragm material. I didn't open it up to look at the insides.
YS Japan doesn't seem to respond to emails too well. Though they turned around the warranty repair within a month. They never ever responded to my emails, asking then what they actually found wrong with my engine.
Wish you well towards getting it all sorted.

MarkGrabowski

Does the non-cdi version have these issues as well? (pump, bearing. etc.)

pattratt

My Feedback: (1)

Mark

No, not as bad and I can not explain why as the pump and regulator are the same?

Dick

rcpattern

My Feedback: (45)

I would be very interested to know if some of these issues are caused by lower oil content many are running in the CDI versions. Granted, that would not be the issue on a new motor, but I wonder if some issues on others are starting to pop up due to long term use with a lower oil content. I always ran at least 20% oil in mine and never had the bearing issues and such that others have experienced.

Arch

bjr_93tz

Hi Arch, I think the oil issuse was raised a while back and IIRC a lot of the UK flyers were having pump proplems even with 20% oil.

My rear bearing failure occured using a home brew of 20% coolpower blue, 15% nitro with an APC 17x13 prop.

A while back after the bearing change, a couple of times it would develop a bit of a cough which I couldn't tune out and I'd find a lot of oil in the clear tube running from the crankcase to the regulator so I dropped back to 15% oil and 15% nitro and it seemed to run fine until now. I've mainly been running a repitched 18x11wpn since then.

The pump and bearings situation reminds me a lot of the theories and speculation surrounding the old OS peeling liners issue, 20 years down the track we all know that it was happening irrespective of fuel/prop/plug/plane weight or whatever other excuse could be thought of at the time, but it didn't happen to everyone and it certainly wasn't the fault of the end user (in most cases)..

bwick

Bryan and I have come to the conclusion that most pump and bearing issues people are having (and we experienced ourselves) are really the result of failing plugs and/or modules. Every time something in the ignition system has problems, whether it be the module, the plug, the pickup wire, etc. the motor will always act rich or just not run at all. The problems with failing pumps and bearings happen when a plug starts to go bad or a module starts acting funny or what have you. The motor suddenly and inexplicably starts to act rich and because it's a gradual thing it's very easy to attribute this to small changes in the weather or the engine "breaking in" or whatever. The truth is neither of these things require as much adjustment or headache as a bad plug! If you don't know something is wrong with the ignition system it can be a VERY frustrating experience that ends up with ruined pumps and bearings because the engine runs HOT and lean. I think it's possible to run the lower oil content fuels as some have reportedly done for long periods of time, but if you are not on top of the motor at all times the lack of oil + lean running will ruin a pump in a heartbeat. It's happened to Bryan and I several times until we finally started catching on. The good news is if you know this it's much easier to recognize and remedy before the pump really gets ruined. I do use CoolPower 30% Heli LS (~20% oil or something honestly not exactly sure) to give myself a little room for error though. Knock on wood haven't had any pump issues, and I don't think Bryan has either, since the worlds. So, long story short, if your 170 CDI starts acting rich, burbling in the mid range, idling unreliably, or running hot (we just use our hands on the tru-turn after the flight as a gauge) then don't touch the adjustments! Reach for the plug wrench and change the plug! If you see carbon build up in the plug there's a good chance it's bad. Scrubbing it away doesn't fix that problem either so toss it in the trash once you confirm it was the problem. I understand the plugs are expensive but I guarantee you it's less time, money, and worry then a ruined pump or bearings. These are top of the line, competition motors and deserve respect and attention. If you're looking for the ease and convenience of electric you're not going to find it with YS, but the added length of my practice flights, presence in competition, and just flat out love I have with my YS's trumps everything else. We are few and far between these days but nitro is still flowing through some veins out there

-Brett
Team YS Performance, and proud of it

pattratt

My Feedback: (1)

Hey Brett

I pretty much came to the same conclusion on plugs as being the primary problem on the YS. There is no one that was a more "Die Hard" comitted YS person than myself going back even before you began flying! After having said all that I have to admit that everything being what it is now I would not even consider going back to YS or any other internal combustion engine power source for a pattern aircraft. I too was concerned about flight time with electric but I found it to be a non issue. In fact on any given practice day I am getting probably 25% more actual "air" time! The quality of my practice time is much much better not having to worry about weather or not the engine is set correctly or if I am going to loose a plug. I hate to say it but electrics now have more power, no vibration issues, quieter, pretty much problem free, and many many more options in aircraft and motors. There really is a reason why so many are making the switch and not going back!
Now if I could only figure out how to remember to hook up ailerons befoer taking off I might be able to learn the F-11 instead of putting aircraft together in the shop!!

Best Regards
Dick

Team Old & Stupid

bjr_93tz

Thanks Dick, the IC vs Electric debate falls square into the same debate as LP's vs CD's. After restoring an old turnatble that belonged to my Father I was asked at a dinner which I thought sounded better, record's or CD's? After a brief pause I suggested a more appropriate question would be which gives the most pleasure and satisfaction to listen to... and for that, a quality cartridge mounted on a well set up turntable wins hands down.

It just got the better of me today so I ripped out the pump and the piston in the pump is worn out as well as the cylinder.

I can't say what mechanism caused the pump piston and cylinder to wear out so quickly? I didn't wind the guts out of the motor to prime the pump for the first start of the day, however I did disconnect the fuel line at the end of the day and let the motor run out of fuel, so the pump would have run dry for a few seconds at the end of each day. I was also in the habit of flying 3-4 full tanks (2+ schedules each tank) with no cool down between flights on practice afternoons after work. Half it's life was spent pumping 20% oil the other half 15% oil.

Looks like a new pump is first item on the shopping list....

Torben Parsberg

Hallo
I have also have some pump problems after 50Ll fuel on 1 170 cdi low oil and 30l fuel on a second 170 cdi LO
my pump problems where the Alu is worn inside pumpe house ,, made off the pump valves
so i drill out 6mm*2mm in the pump /house and put some hard 6mm braze tube in ,, and grind after with fine water sanding paper, grid 2000
and then some new pump valvs..
it taks a½ hour t made and costs " nothing" ok some valvs
hope it help some one ..

bjr_93tz

Hi Torben, thanks for the pictures. My pump looked ok in that area but I cleaned it up anyway. I have posted pics of my "problem area", that being the pump plunger.

It can bee seen that the top 1/4 of the plunger is no longer shiney and measures a smaller diameter than the rest of it. Not only that, but the cylinder the plunger goes into is worn as well.

You can insert the plunger about halfway in backwards where the mating surfaces aren't worn and it feels a nice smooth slip-in fit. Turn it around the correct way and it wobbles it's way in and when fully inserted is quiet happy to rattle around, not at all how it should be.

No word from YS yet....

topiwala

Hi All,

bjr_93tz

Hey Topiwala, looks like they fitted a brand new pump, given the orange regulator diaphram and seat inserts.

No reply from YS to my e-mail, although they have been on holidays until 5th January so I forwarded my e-mail to where I purchased the engine and asked them to approach YS on my behalf.

bjr_93tz

Still no reply from YS and no word from where I bought it other than that they have notified YS and are awaiting a reply.

YS might be getting all hot and sweaty over their "new" DZ175 but I can gaurantee that if I have to put my hand into my pocket to fix the paperweight that's sitting in my plane that's only done two comps (and missed two because of mechanical problems) I certainly won't ever put my hand into my pocket for any new or otherwise offering from YS....

Brett

topiwala

Gents,
Has anyone here used a 5 cell nicad/nimh pack OR a 2 cell LifePO pack for the YS CDI ignition unit, without regulators. I'd like to know if the unit will handle a 2 cell LifePO pack. It should do if it can run with a 5 cell Nicad.Nimh pack. Looking forward to some replies.

Chrs
Mayur

UKpatternflyer

Thats a big difference from 5vV to 8.2V. I use a Powerbox digi switch which regulates to 5.5 V and gives you a perfect switch as well. I run both airborne pack and CDi in my Axiome without issue using TP 730 2S packs.

Keith

topiwala

Hi Keith,