NEW YS-110 idle attitude problems...

The engine its mounted inverted with the tank at the CG, it can be adjusted to idle around 2500 RPM's with no problems; you can maintain it idle the whole tank if you want.

The problem comes when you change the attitude of the plane; if you put the plane nose up or inverted it would accelerate and then die (lean), if you go nose down it will just die (rich).

The symptoms look like an under pressurized system, so I check the pressure built in the tank and it seems poor to me, so after checking for any possible pressure leak(every thing was OK; I tried four different check valves 2-YS, 1-Tettra and 1-Cline

YS and Tettra: same result poor pressure.
Cline: The engine was not able to pressurize the tank, the pressure coming from the engine was not enough to open the valve.

I check the fuel pump ducts and the silicone gasket for any leak or obstruction; nothing found.

Could it be a misalignment or defect on the disk valve?
Any other suggestions???

Thanks,
Joaquin

You probably should see what the distributor says? Sounds like your cover is turned around or something wrong with the diaphragm? As far as pressurizing the tank, it shouldn't have much to do with the diaphragm? That's timed by the crank. Maybe you have a crankcase leak?

On the Cline duck bill check valves, they rarely ever work to begin with. The rubber is stuck together. you have to nudge them open the first time with a pencil or something.

Good luck,

Jim

YS Guru's where are you???

Joaquin,

When the engine is at idle, it is not quite pressurizing the tank. I would up the throttle a little for a few seconds to get the tank pressurized properly. Anyway, you should idle reliably at 2000.

Also check that your regulator screw is flush with the housing. Other than this, I do not know what to suggest except to ask Dave Shadel himself in the YS Engine support forum.

Azhar

Are your pressure and fuel lines backwards? You need to go above idle to get some pressure in the tank. How many tanks have you run through the motor? If this is the first tank why are you even messing with nose up/nose down and idle. bring the motor up to about 4k and let it run for a couple tanks then start your adjustments(put the low end back to factory settings on the initial runs!).

Like the other guys have said, the YS operates on draw rather than pressure at idle. What you are seeing is very normal IF you are changing the attitude for a long period of time. Think about it, how long do you operate the engine at idle with the nose straight up while flying?

John

to my limited YS knowlegdge.
My YS63 runs on a suction just like most of the other RC engines at 2000RPM or below. And anything above 2k it starts pressurizing the tank, and starts regulating it thru the regulator.

I am sure by now, that you probably have ran about 4 tanks thru it. So it should be ready to start tweaking the system.

I am sure you know this as well, but since you didn't state it. What fuel are you running. As you know YS's like 20/20 are higher nitro contents. Also is the fuel fresh, I can tell on my little YS 63 when the fuel is starting to get old,.

Also what plug are you running. Probably won't have much to do with your problem, but most people I know, run a OS "F" to clean up the midrange.

I know I haven't dropped much help with you. Like somebody stated above, you can always ask Dave in the YS manufactoring forum. He has helped me a lot. Just state everything you have done, what fuel, plug, and prop. that you he has all the info their and he won't have to ask.

Let me give you some feedback why I tried different attitudes on ground.

First I put two tanks for break in on the ground, then I and went into the air!!!
For the first flights I added a button to offset the throttle so the engine would run at 3k at idle and the turn it off just for landing.
I adjusted the idle to 2.5k with no problems on the ground.
Third and fourth flights, using the throttle offset (3k) 6 minute flight ended dead stick.
So I think: OK maybe my adjustment at idle was not good...
I verified the idle and everything was just O.K. for the test I leave the idle from 30 Secs to around two minutes and apply full throttle
with no problems at all.
I went to the air and ended with dead stick, so I tried two more flights (that also ended on dead stick) looking for the flight path used when the engine dies. and thats how I ended checking the attitudes...

After some more tests I think I'm around 10 tanks

Jaoquim,

Is this engine in a cowled application?? If so you may have an overheating problem. Make sure there are enough holes to vent. You may be rich on the ground, but if the hot air in the cowl does not get a chance to vent, it will overheat the engine.

Azhar