Dave, hi !
Excuse, that I interfere, but at me the same problems at average revolutions (3000-7000 RPM).
My 63 is running rich.
Strong (for the helicopter) vibration in this range.
Fuel: 20/20
Plug: O.S. “F”
Prop: 12x8
Fuel Filter: Yes
Tank: Ok
High Speed Needle: 1 1/3 turns out (best result 10100 Rpm)
Low speed Needle: 0.8 turn open from full closed
Regulator : 1 turn out (factory set)
The engine is run in on the stand installation on the helicopter (if you remember we earlier spoke about it)

I cleaned DIAPHRAGM (there it was not so clean...)
I adjusted the valve on 0.04 (factory set - left 0.1, right 0.15)
I long achieved steady work on average revolutions, but could not make it...
At work on on an average mode and transition on single the engine stop also spits from carb fuel...
At work on average revolutions, then on maximal, THEN AT ONCE ON SINGLE - ALL ok.

I tried fuel - 30 % nitro, I tried fuel with fluid oil, does not help... What to do(make)?
How to remove vibration?
Still the question - as by the helicopter another - that what temperature mode needs to be observed cooling?
On the stand the motor was heated in on 2600 and on 9000RPM. up to 70 C. On 10000 and 5000 cooled down. - 52 C.


Little bit short cranshaft YS:

A 12x8 prop on this engine is TOO MUCH!

I am sorry but I am not able to understand all your other questions. Please try to rephrase them and I will try to help.

Thanks,
Dave

Who writes the instruction?
"PROPELLER INSTALLATION
Due to the high torque of the FZ63 engine, we have equipped it with a double lock system for safety.
1. Mount the propeller and tighten the rear nut. Next, tighten the front nut as shown in Fig.1.
2. Select a good quality propeller that will turn in the 9,000 to 12,000 rpm range. We recommend sizes 11x7-11x9,12x6-12x8."

Ok. I put 12x6 and try.

Excuse for my English. A question was 2:

1. I should observe what temperature mode?
Tell range Min and Max temperature, please.
I shall carry out(spend) gaugings by the helicopter and if it will not correspond(meet) I shall change system of ventilation.(Cooling fan, Fan shroud)

2. I can not achieve steady work of the engine on average RPM.
It rich. That I did(made), I have listed above. What it is wrong?

I cannot quote temperature numbers as I do not know what they are.
What is brand name of fuel you are using?

Handmade fuel:
Nitro - 20%
Metanol - 60%
KLOTZ KL-100 - 20% (OIL 20% CASTOR)
In Russia it is not sold Brandmade fuel.

My guess is that your fuel components are not what they should be in terms of quality. YS engines are very sensitive to poor quality fuels and this may be the problem. ie, water in methanol, low percentage nitro.

On my Kysho Concept 60 SR II Graphite stands YS 61 ST II. He works perfectly and without problems on this fuel. I tried fuel from him - 30 % nitro and 22 % Klots. At me is OS 52FS Surpass. It too not stop on average revolutions. The Russian factories which are letting out metanol and nitro technological enough.
And I not poor to buy fuel on a dump.
I think fuel here not It is guilty.
What else there can be reasons?

Svkov, I am out of ideas. Without seeing the engine it is impossible to know what the problem is. I know it is hard for you to send the engine to us for service, but that may be the only way to fix it.

And unless with short canckshaft it(him) will accept on a guarantee?
Perhaps I shall twist a little more, I shall try...

Since the engine has been modified, we cannot warranty it. Where did you buy the engine?

www.heli-kraft.com

We do not work on anything which wasn't purchased through our distributors. Sorry, but you are on your own.

No problem.
And silly questions will answer?
Ys 61 ST II is bought on www.heli-world.com
on a guarantee?

HAHA ! Yes to silly questions.

No warranty on anything bought outside the US.

www.heli-world.com - Ñalifornia

Sorry, I know them as Helicopter World. My mistake.

All has turned out!!!!!!!!
On average RPM more problems are not present!!!
It is a shame to admit, but the reason was that I to make the engine lean TWISTED(clockwise) Low speed Needle...
And you see I even translated the instruction on Russian for our site - www.rcdezign.ru. What carelessness!!!
Now the engine works stably.
High Speed Needle: 1 1/2 turns out
Low speed Needle: 1.5 turn open from full closed
Regulator : 0.85 turn out
Best result 12x6 - 13500
12x8 - 10150
Even at elimination of bad tightness Back Plate Gasket (with the help sealant) the compression has raised(increased).


At me three more silly questions:

1. The low speed varies 1900 to 3300 RPM.
It depends on a mode with which I has passed on low speed.
And should be?

2. Push Rods+Tappet Adjusting Screw Set In the bottom position (when not this, and other valve is open) have strong (0.5 mm) palpation(luft) to the left - to the right. In the top position of it is not present. It is normal?

3. And why there is no helicopter version YS 63?

Beforehand thank for the answer.

Dave?

If the low speed varies this much, something is leaking, but I do not know what.

Some side play in the rocker arms is normal.

There is no demand here for a 4 stroke heli engine. The 91 was once made as a heli engine and no one wanted it.

Dave