Regulator flush with the case...in is lean out is rich. Should not have to touch it!

High speed start at 2 turns and lean from there.

Low end start at 1.5turns and adjust from there...In is rich and out is lean.

Procedure:

Set the top end. Click or two at a time and wait several seconds for it to respond. The response will not be instant as the fuel has a long path to travel before it burns.


Then bring it to an idle of 2000rpm not 2200 and not 1900 right at 2000 with your TX trim. Watch a tach to make sure its 2000 even. This is a critical RPM as the motor is not being force fed fuel it is sucking it from the fuel system. Above 2000 rpm the pressurized fuel system is forcing fuel past the regulator and to the needle valve. In the first 30 secs of this idle if it rises up then sags out its lean (surges)...If it just slowly dies off its rich.

Once you make any adjustment on the low end...Go to full power clean it out for a couple seconds and then back to right at 2000rpm. Watch for same symptoms. If the idle will not trace right back to the 2000 rpm and hits like 2500 then slowly comes down to 2000 its lean. If it smoothly hits 2000 and then slowly loads up and drops off its rich. The first 30 seconds are the key to watch on the tach....Look for a little surging like 2000 to 2500 and back to 2000 this means your close and on the lean side.

Next is the regulator screw adjustment. Should not have to touch it.....If you do it will be because the mid-range is rich or lean. Same procedure as the low end but this time the rpm number is around 4000 rpm.....When adjusting the pressure regulator you will need to re-set the High and low ends.....As both will be affected. Max movement on the reg screw is around 1 turn either way from flush and most often they are turned in slightly from flush if you need to move them at all....I would say 1 in 20 motors or even less might need the regulator adjusted. And that is might! Go slowly and in 1/8 turn increments.


Key points don't run it too long on the ground. Once it gets hot you'll never get it set. If you are on a cool day like 70's its better. But don't run more than about 2-3mins on the ground. This will cause the motor to heat up past operating temps and you'll be chasing your tail. If it gets hot shut down and let it sit for 15 mins or so to cool off then start where you left off. Another key point is when setting it up use a smaller prop like a 15-12 or 15-11 this will load the motor less and make it work less. RPMS will be in the mid to high 8000's and this is good. If you really feel like you want to load the motor down...don't run it below 8000.....Ideal is 8300-8500. My personal opinion is run a 15-11 or 15-12 on 25% nitro is you feel like a 16inch prop go to the 16-11 and see if its not loading to the 8000 -8100 this is a little low on the RPM scale. Try some more nitro like 30% heli. If you really want to run the motor with that specific prop....Key on the YS motors is to let them run at the right RPM regardless of what the numbers on the prop say...8300-8500 will make good power on most of the props out there. So if you are running a 120AC or you are running a 140FZ Sport or the 140L....Run them in the same RPM range....No matter what the props are. Pick a prop that laods the motor properly. If you do this you will have less problems down the road. Trust me!....More RPMS and you are not loading it up and too low RPMs below about 8100 and you are loading it too much and will having troubles sooner than the guy at 8400...



Reg flush-low end at 1.5 turns and a set top end should run close. My suggestion is make adjustments till it seems reliable or is close then fly it. The flying will cool the motor off then next flight make a small adjustment to the low end and try it again......

Note: Too lean the low end bleed screw will mean the motor will not die when you pull a kill switch. Check the carb to be sure its closing and if its closed but the motor is ticking over you might be too lean or have a leak somewhere. Meaning the air bleed hole is too open and its leaking too much air past.

Another thing, you don't want a instant transition, where the motor screams to life instantly from idle to full power. This is a lean condition. You want it to smoothly take say 1.5-2 secs even though you throw the stick forward. This way the bottom end is a little on the rich side. Otherwise the leaner bottom end will starve the motor as you transition it. Remember it take a little time for the fuel that is going thru the needle valve and into the carb to reach the fire. If you are setup for an instant transition then when you throw the barrel open it will be instantly lean then catch and go. This can cause un-do wear and tear on the piston-ring and liner, also it can lead to an occasional backfire and cause other damage.

Hope this helps


Troy Newman