YS 110 troubles also
 

Mine sound very simular to whats happening with some of the other YS110 engine but mines
starving. Idle setting screwed in all the way or out three turns makes no
difference. I've done EVERYTHING that I can't think to do. Mine, however after 3
new fuel systems, plugs, cleaning, O rings, seals, fuel, I've found at the idle
below 3000 the fuel line from the front of the crank to the carb is full of air,
at least 3/4 of the line is all air. bump the motor above 3000 rpm's and the air
in the fuel line mentioned goes away. Sitting on the ground it'll idle all day
long, but in the air flying, idle set at 2200 or so it'll quit 9 times out of 10
at or about base leg on landing. It was bought used and has had this problem
from day one. I own 4 other 120-140 model YS motors and am well pleased and
never had ANY troubles that wasn't quickly sloved, but this problem has got a OS
91 now on the nose for a quick fix, but really would like to get hte 100 hoss back on the nose. It shouldn't be that big of fix, but I have
to go with Dave's suggestion and send mine in also. If this is and issue that
only a pro can fix(reworking a diapham) than it's almost in need of a design
change. However there are some really tiny parts in the regulator that can
eaisly be put together wrong. Mines coming your way to soon as the mail runs
Monday, Thanks, Dave.
Jamie in Alabama

RE: YS 110 troubles also
 

Service will get it straightened out.

RE: YS 110 troubles also
 

I asked about the bubble in the line and have been told it is normal. Seems odd to me but that is what I was told.

It seems they either run great or are problematic. I have one very similar to yours it will idle forever on the ground. Transition to full throttle is perfect. 15-20 mins of idle, full throttle and taxiing with no problems. But get in the air and go to idle for an approach and it goes dead stick.

It is not the tank since it was running fine with this setup previously. Changed the plug only 10 flights ago but will do it again just in case. But could a plug really cause this to happen?

RE: YS 110 troubles also
 

Small bubbles in the line from the regulator to the carb can be a normal. These are not always a concern. What happens is the line into the regulator is under pressure. About 6-8psi. When the fuel gets past the regulator and in the line to the carb its no longer under this higher pressure. The resulting expansion can make a tiny tiny bubble from a foamy fuel tank bigger and you will see it.

This doesn't always mean that your engine is not working properly. However if you have a leak then lots of bubbles can be in this line and this is not good.

Small bubbles by themselves are not an issue. If the engine is running properly then usually some small bubbles can be seen in this line...Not always and it usually has to do with your fuel tank setup and if you are getting foaming issues because the tank is vibrating.

If the engine is running a little lean on the low end this can happen. try to richen it slightly to where it wants to load up just a little on the first start up. This will affect you taxi and idle when the engine is cold. It takes a few minutes to get up to temps. If your idle is perfect from a cold start its likely slightly lean. A lean condition like this can ruin a glow plug in the first run. So 10 flights well....these engines don't use spark plugs like in your car. The plugs can be fragile and sometimes you can get one that is not right out of the package. Its rare but happens. I have seen running the engine out of fuel in the air destroy a brand new plug in the first flight.

This goes for any glow engine and is not really specific to the YS...however all 4 strokes tend to be a little more critical on glow plug performance. Just because it glows doesn't mean its good. It like my father in law says about tires. All it has to do is hold air and roll......yep that makes it a tire...but you don't put that tire on your Ford Expedition and hit the highway at 70-mph. YS engines are high performance engines. They can sometimes be finicky about glow plugs...it depends on your choice of fuel, prop and environment. Usually the higher the nitro you run the less critical all these little things become. Try to do it on 15% and you will have to have things right on the money. Throw some 30% heli in it and since everything is now get adjusted richer the settings are much less critical, and the abuse on glow plugs and so on is less

Troy Newman
Team YS

RE: YS 110 troubles also
 

I purchased a slightly used 1.10 a couple of weeks ago and just got around to starting for the first time last night. It fired right up and idled fine. However, when I tried to advance the throttle it would act as though it was leaning out, and then pop to a halt. I had the high end needle out 3 turns. I tried several different setting on the high end needle and couldn't get it to rev. I went through the steps and set the regulator flush, the low end at 1 1/2 turns out and tried from 5 turns out all the way to 1 1/2 turns out on the high end and still could not get it to transition. Then I notice all of the bubbles in the line between the regulator and the carb. These were no small bubbles. At times it looked like it was all air. I pulled the regulator off and the diaphragm looks perfect. The gasket looked good as well. The fuel line from the tank was clear of bubbles so I am not sure quite where the bubbles are coming from. I have read through every thread that had mentioned bubbles in this line but still don't understand how this is supposed to work properly with bubbles entering the carb. I don't have time now to send it in for repair as I have a race in a little over a week. Any ideas you can give me will be greatly appreciated.

Thanks, Terry

RE: YS 110 troubles also
 

Well not always does the regulator end up flush. First of all that is a starting point. I would say that most end up around flush with the case on the Non-external regulator engines.


Next if you have lots of air bubbles then you have air leak somewhere.

It could be lots of places. The regulator gasket? The carb bolts, and gasket, In fact it could even be up at the air box...this is coomon spot for a leak but will likely not cause air bubbles in the line. The quick pop or bang to a stop is not good. The mid throttle range is mostly controlled by the regulator setting. However the HS does play a role. If the HS is out 2.5-3turns then it is open far enough on a normal engine....The regulator is likely lean...but it could be lean from various reasons. Usually a bad diaphram will not act this way at all...so its likely not the diaphram but it could be the plunger stuck closed or not moving freely or it could be a piece of dirt or debris in the regulator. The little holes are easy to plug with dirt or debris.

The air bubbles could be the result of a leak or they could simply be a symptom of blocked passageway in the regulator.

Check fuel filters, make sure check valve is working the right direction to keep air in the tank... and its holding pressure in the tank. If the tank is not holding pressure then you will not be getting fuel to the regulator and this could where the "bubbles are coming from" as there is not enough fuel pressure in the tank to be running at the rpm you are asking it to run.

If its doing that lean run thing back it down right away...this si a lean conditiona nd since you are running at high RPMs 1/2 throttle then it could do the explode thing when it detonates and stops.

You advance the throttle slowly and if starts detonating then back it down...adjust the reg or HS and then bring the power back up.


The HS has a little effect on transition, the Rgeulator mostly controls it...the Low speed air bleed screw has nearly nothing to do with transition. It only fine tunes the mixture when the engine is at 2000-2400 rpm above that the air bleed screw does ZERO for the engines mixture. If you HS speed and Low speed are close to "normal settings" and are still rich of those normal settings then the regulator needs adjusted.

I had a buddy with a 110FZ and it needed 2 full turms open past flush (this is richer on the reg) to get it to run properly. Flush was a normal starting point. Once it was opened up his engine ran perfect it just needed more regualtor pressure or it would detonate on throttle up.

Low end should never be more open that 2.5-3 turns (this screw works backward as its an air bleed not a needle valve) CW is rich and CCW is lean on the air bleed low end screw.

HS should not really ever need to be richer than about 3 turns.....

Regulator is somehere around flush...but in your case it needs to be open more. If its detonation problem continues try 1/2 turn CCW on the reg and see what happens. It should get better with this course adjustment. It you go out about 1.5-2 turns and it doesn't seem to get any better at all then there is something wrong internally and it should go back for service.


Troy Newman
Team YS

RE: YS 110 troubles also
 

Hi Troy,

Thanks for all of that great info. I was running out of day light last night and wasn't able to thoroughly check things out until today. I did a pressure check and it turns out I had a small leak in the pressure line. Just as you said, that is what caused the bubbles in the line. It makes sense since the engine was trying to draw fuel that wasn't there. Now I have to get everything adjusted again since I turned everything last night trying to get it to run.

It seems like I have the low end pretty close. It does not start gaining or losing rpm at 2000 but it is not totally smooth there either. It spits and sputters a little. I set the high end a little off peak and it doesn't hold a real steady rpm either. Perhaps the regulator is not ideal where it is set? I used the directions off of the [link=http://www.probuild-uk.co.uk/factsheets/ys_engines.php]ProBuild Fact Sheet[/link], but it doesn't really address the regulator adjustment.

I suppose I should try a new spark plug as well. It has the plug that came in it. The previous owner told me he had run only one gallon through the engine. It may just need some more break in time.

Thanks again.
Blessings, TErry

RE: YS 110 troubles also
 

A new Glow plug is a must...especially when you start having troubles.


OK think of the engine as this...it never sucks fuel unless its at 2000 rpm. Anything above 2000rpm and its being force fed fuel because of the pressure in the tank. The regulator controls the pressure at which its being force fed fuel. The HS needle meters this fuel again at the carb.

a Pin hole in the pressure system will do it...and this will toast the plug too.


Troy Newman
Team YS