This is my first YS and went today to fly it mounted in a Kyosho Sensation. Prop APC 12x7, fuel 20/20 with some castor added (thought it would be right for breaking in). I ran 1 liter of fuel through it very rich beginning at 9000 and ending at 10000 rpm. Transition was good and also idle so I decided to go flying with the same setting at 10000 rpm top (the manual recommneds to run ten flights rich to finish the running in). Filled the tank, fired the engine and the problems start. The revolutions start oscillating. It seems to starve for fuel and then it gets a lot of fuel. It cannot mantain the iddle, it just stops. I can only get it to run at half throttle and it gets this oscillations. If I put more throttle it just stops. The high end neddle does not get it better, and when it stops there is tank pressure and it holds it forever.

I suppose it might have ingested some dirt but would like to hear any suggestions before I start to open the engine.

Thanks in advance,

Joan

Did you use two filters? one between the engine and the check valve and the other between the tank and the regulator?

You obviously don't have any dirt in the check valve, but your regulator may be full? Why don't you check your tank pick-up clunk and connections before you go tearing into the regulator?

If you do go into the regulator be extremly careful to put everything back exactly as it came off. Minus any dirt or lint that is.

good luck

Jim

No, I only use one filter. Do you think it is necessary to use a second filter between regulator and check valve? I have opened the engine and I have only seen a very small dirt in the regulator. Everything else semeed correct but I have not checked the check valve. I will clean it tomorrow before firing the engine and hope I have luck. I have also adjusted the valve clearance but donīt think that it was the reason of malfunctioning.

It sounds like you are on the right track. If you found some dirt in the regulator then there is probably some at the filter and the needle valve too.

You obviously don't have a problem with the check valve yet but your turn is comming if you don't get a filter between it and the engine before long. I don't mean to quit using the plane. Just the next time you are procuring hobby parts, pick up one and install it.

Good luck

Jim

First...

Why in the world would you add Castor to YS 20/20? It has the recommended amount of oil ALREADY in it. Just need to run a little bit on the rich side all the time, especially for the first few flights. You cannot (properly) break in any engine running it any differently than you will when you are flying it after it's broken in. More oil can hurt, contrary to popular belief! The engine will run at a different temperature with the extra oil as opposed to without it, and most likely it will run hotter. Not good.

Secondly....

Why in the world are you making adjustments to the valve clearence after only a few minutes of running? This is just one more way dirt gets into the engine. Are you planning on replacing the valve cover gasket when you put the cover back on? If you don't yet another place for this high performance, high internal crankcase pressure engine to leak, causing more problems.

I'm sorry for the attitude, but I get a little tired of hearing people talk bad about YS engines, come to find out they have "tinkered" with them prior to even installing them on the plane. Not saying you are doing that, but you could be on your way..........

Just one example from one of the many YS engine powered planes I own. I've got a pattern plane with I don't know 500, ten minute flights on it. I always run it on the slightly rich side. Never, EVER have I had to take apart the regulator, I've never adjusted the valve clearence, and it starts on the third flip (first flight) and on the first or second after that. Idles at like what seems like 250 RPM and will pull the plane verticle as high as my 37 year old eyes want to look for it. Dead sticked twice.......both times I was having so much fun I ran it out of methanol!

YS engine instructions:

-Do NOT touch anything on the motor before it's in a plane ready to be flown. Get a pattern guy to help you set it up, untill then dont touch anything.

-Use only Powermaster YS 20/20 or Wildcat YS 20/20, dont ask just do it.

-Always double, triple or even quadruple filter your fuel.

-If you do have to take anything apart, always, ALWAYS replace all gaskets/o-rings you remove. If it's the regulator get a new spring and regulator diaphram and just replace them as well. I personally do not touch any of the internal engine parts with my bare hands (oils/acids) not good, use gloves.

-Remember the low end is set from the factory to run on YS 20/20 fuel, dont touch it. If you have to it's opposite of most needles, turning it in richens, turning it out leans.

-Use Quality plugs, I've had the best luck with Enya # 3, OS type F not in any particular order of preference.

-Arrow on check valve always points towards the tank. I checked and yes I do use a filter before the check valve.

Best of luck to you, YS is a great engine, best glow motors I've ever run.

Scott

Scott,

This is my first YS engine and I am trying to be positive with it as I am with all the engines I own. I am not the usual guy that always have problems with my engines and I am satisfied with them all with no exception. I hope to say the same with this YS, it is only that I am having problems now, and being different from other engines is why I am asking for oppinions. I do not like to disassemble engines and just do it when it is necessary.

The reason I have added some castor to my 20/20 fuel is because I think it is a good idea for breaking in. The manual say to run between 20% and 24% oil ( I am saying this by memory) and it can be synthetic, castor or a blend of them, so I am not doing anything that the maual does not say. My fuel is home blended because fuel price in Europe is not the same as in the States and I have been blending it by myself for some time without problems. When the engine is broken in I will run 20% synthetic oil.

The reason I did adjust the valve clearance is because the manual says it should va between 0 and 0.1 mm. clearance and it had 0.2mm. If I had seen that the valve cover gasket had been damaged in the disassembly I would have changed it.

I am glad to hear that you are satisfied with your YS engines and I hope to say the same in the future.

Having said all this I just fired up the engine this morning and the problems had disappeared. I ran a full tank through it without any problems and hope that it will continue to run the same way. I am not sure what the real reason was because the dirt I found was really small, but I expect to fly a lot before disassembling it again.

Thanks,

Joan

Two people had the same symptoms at my field today with their YS 63's. Turned out both had leaks in their fuel tanks. Double check all connections and make sure the tank holds pressure.