Union Models

Hi Guys,

Another YS 63 problem......

I bought a second hand YS63FZ some time ago. It had done a fare amount of running so
I sent it away for servicing. New piston ring, new diapham, new bearings and the valves bedded in again, as it was down on compression.

When it came back, the service agent said he made a modification in opening up the air bleed hole slightly on the throttle barrel. Apparently he said this was to help with a better set up ?
The engine runs, but it's not perfect.

The thing is, I can get the engine to run to full throttle 10500 rpm, hold 4000rpm for 20 seconds but the tick over will not hold 2000. It starts to drop rpm off.

I've leaned the low speed needle to be 3 turns out. If it's set 1 turn out from fully closed, when the engine starts at 1/8 open throttle, rolls to full throttle, the engine coughs like crazy in the transition phase.

I've leaned the low speed needle until it's just ready to pop out, still will not hold 2000rpm. Best I can get to hold steady is 2200 at 3 turns out.

BTW, there are no leaks, the check valve is okay too.

Is this modification causing issues with the tick over?

I'd be grateful if anyone could explaine this.

Thanks
Mike

petec

My Feedback: (58)

Let's get the high speed and regulator dialed in first. I personally am not a fan of the 4000 RPM method as I have had mixed results. Looking at your post statement that "the engine coughs like crazy in the transition phase" tells me the regulator is not spot on. Is it blubbery rich or a lean misfire? Once you get the regulator dialed in go to the low speed needle (Set the regulator with the LS needle 1 1/2 turns out)and adjust so your idle is 2000 to 2300 RPM as anything under 2300-2400 RPM is sucking fuel at idle as opposed to injecting it from the regulator.

Union Models

Hi Petec,

Thanks for your reply. My thoughts were with the regulator not bang on.

Whats your prefered method of setting the regulator ?

As a test for the low end setting, I removed the carb pipe and there was may be a drop or so of fuel comming out when it was on tickover.

Mike.

petec

My Feedback: (58)

I have been using this method:

http://www.julton.net/Fact%20Sheet%20YS%20Engines.html

The regulator will control the transition froom idle to full throttle. Too lean and it will hesitate and then catch up, might even backfire and throw the prop if your jam nut is not tight. Too rich and it will stumble and smoke. When you have it right, the engine will spin up happily as you roll into the throttle.

Also, do not turn the regulator screw more than an 1/8th turn at a time as small adjustments here have big effects.

Union Models

Many thanks for the info...

One last question. I have read a few time the comment ' Don't chase the mixiture ' whats ment by this ?

Mike

oskartek

Union Models,

"Dont chase the mixture" is explained fairly well in the Carburetor set up section For YS engines here,

http://www.geistware.com/rcmodeling/...er/ys_main.htm

Good luck Happy flying, Oscar

oskartek

petec,

If I'm not mistaken I think that http://www.geistware.com/rcmodeling/...er/ys_main.htm

is word for word the same as http://www.julton.net/Fact%20Sheet%20YS%20Engines.html

I didn't notice until after I posted.

Happy flying, Oscar

petec

My Feedback: (58)

oskartek-they are as they were written by the same person.

Mike - That means after each adjustment roll it to full throttle and back to idle.

Union Models

Okay, thanks guys. I'll go away and have another go.

Mike

Union Models

I had another attempt with the YS63.

It's now running a lot better. Tick over is bang on 2000 rpm. I can hold the model verticle and it will still hold tickover for 30 seconds +. However, to get it to hold 2000rpm tick over, the low speed needle, needed to be set 4 turns open. It refused to hold tickover with it set 1 1/2 turns open.

Transition is smoother ( regulator set flush )

Full throttle 10k high speed needle set 1 1/4 turns open, APC 12x8 20%nitro 20% Medium viscosity oil.

Mike.

petec

My Feedback: (58)

It's great to see someone give the engine what it wants...and the engine rewards them. Good to hear your are tuned and good to go.

Union Models

Thanks for your help

Mike