Troy, I recently purchased a used ys 140l and am haing some problems with it. The engine holds a great 1750 or if I want 2000 rpm
idle and will run for what seems like forever. When I advance the throttle it transitions well but at full throttle it seems to lean out even
with the needle 4 turns open. I have an 18 x 6w APC prop on it, I have tried others but the same results. THe engine only seems to reach 6 to 7K for about 10 seconds and then it starts losing power then it cuts off. I am using 30% cp heli and I have several ys engines with no problems yet. Have you ever experienced this before?


Thanks
Jeff

Sounds like a piston/ring problem. You should send it in for service. This is a tell tale sign or a scratched liner, or warped piston, or it could be just a well worn out ring.

I would suggest to you that prop is probably too much load. You need to run the 140L about 8200-RPM I would prefer above 8400 personally.

But if you given prop was turning that proper rpm..then you are fine. Overloading the engine down into the mid to low 7000's will in effect overheat it and could cause the problems you are describing. Or it could have just eaten a rock or some other debris and scratched the liner.

It is in need of service for sure.


Troy Newman
Team YS

Do you think the 18 x 6w is too much? I run the same prop on y 120 sc motors at high 8k with no problems. I will send it in asap.


Thanks
jeff

I don't know I don't like those 3D style props like the 18-6W. They are too heavy and I don't like the way they make the models fly.

But if you are hitting the rpm ranges then theya re OK.

To me the 18-6W seems like a bit much....but if a 120SC is turning it up in the right rpm then the 140L should as well. A really strong 120SC will come close to the power of the 140FZ or 140L...I would say about 90-95%. SO yes it should be OK. On the 140L I like the 15-12 and 16-11 maybe a stretch toa 16-12.

Troy Newman
Team YS

I got the engine back a couple weeks ago and finally got time to run it yesterday, it was a huge difference. I ran 3 tanks through it first 2 at about 4k rpm then gradually through 2 more tanks brought it up to full rpm for a short while, I am getting 9k on the same 18x6w apc with the needle set at 2.5 turns out. Engine stays cool, I will fly it tomorrow.

Thanks to YS repair center for a great job. They changed the piston and liner,all gaskets and diaphram, front and rear bearings.
The service was great and very fast.


Thanks
Jeff

Glad to hear it. I will pass along the Kudos to Richard and crew at YS P+S

Troy Newman
Team YS

I finaly got to put her in the air today and boy does that puppy pull. It's on a 1.98 meter 13lb funtana she puls it up and out of sight.


This one is going to be a lot of fun.



Jeff

great news.


Troy