You summed it up Tommy.

I can tell you that the DZ specifically has a very tight set of conditions it wants in order to perform. The first few runs and tuning are CRITICAL. if you aren't experienced enough yourself, seek the help of someone who is. Luckily when I got my first one, I had Jim Ivey to teach me how to set it up. Jim is one of the best in the southeast with the YS engines. His ear for it is uncanny. He can hear subtleties that I can't. I'm learning fast just by being around him. I can set one up very well myself and diagnose most problems fast. But Jim has some kind of zen going on with the YS.

The other key to this engine is that they do require attention. They will let you know in no uncertain terms when they're not happy. The last thing you want to do is try to fix it with the needle. If you're a needle tweaker, you'll blow this thing up. Once it's set, DON'T TOUCH IT!!!!! If possible make it where you can't even get to the needle easily just to remove the temptation. Because every time you start it on the ground, it's a little different first run of the day. You can swear something is wrong when it's NOT. Just fly it. Then if it starts hammering in the ear, ONLY then should you check to see if adjustments are needed.

The other thing I strongly reccomend is a header tank. I use a 2 ounce header tank with the fuel pickup for the engine dead center of the tank. Stiff tube, end of it right dead in the middle. Location of the tank itself doesn't really matter, but the closer to the engine the better. The line to the tank is set up like a vent line in a normal tank, in and to the top. Put a good fuel filter in line before the engine and after the break in the line. The header tank removes all inconsistencies with the way this engine runs. Everyone having a problem I have seen around here is not running this tank for whatever reason. It wants this tank, because it's very intolerant of air bubbles. You have to balance your plane with this tank full, and it gives you NO warning that it's low on fuel before it dies hard and throws the prop. So set a timer and be certain, don't press it.

One other piece of advice if you are used to 2 strokes.......do NOT run this engine to full power cold. Start it, give it a few clicks, and let it warm up, slowly advancing the throttle to about 1/3. After about 20 seconds, you can slowly advance to full power. if you start it and immediately go to full power, say goodbye to your prop, spinner, and maybe half of your face. (Ask Lamar Blair).

As Troy mentioned it doesn't require 30%, but let me tell you, if you ever run Cool Power 30% heli in this engine you'll never run anything else. That actually applies to any 4 stroke in my opinion, all of the guys at my club started using it in thier Saitos and OSs, and the power and consistency of thier engines were noticably different. I'm sure other fuels are fine, Cool Power is just the easiest to get around these parts. I have run it exclusively since the early 80s. The fact that I am now part of Team Cool Power was about 20 years after the fact....LOL

The OS 160 is a powerhouse as well, but it's not the same as a DZ 160. It's apples and oranges, you can't really compare them because they are so different. They make very close to the same top end power, and idle about the same....on the ground....the OS is hard to spool down fast on a downline so if you have a clean fast plane, you have to lead the throttle. I ran the OS 140 for years (and swore by it, still do for many applications) and the hardest thing for me to get used to was the instant throttle response of the YS. It will kick your rear if you lead it too much. You either have to use a broad curve or be very comfortable with the left stick.

Until the DZ 160 came out, I could really see no advantages personally to using a YS in the big picture. Dead sticks were an every day occurence around here, and they didn't make any more power than the OS, so to me it was more of a liability than an asset. Then I watched Jim Ivey run a DZ 160 for 2 seasons straight....it always cranked, always ran, made awesome power, and I never saw him touch it...ever. Went to the nats last year, and for the first time ever, felt like I just didn't have enough power. I stayed at Arch Stafford's place for a few days before the Nats, and he told me "Watch...you're going to get there, the heat and humidity will be ridiculous, and watch...you'll run out of power." I laughed it off. Then he spent the next 3 days saying "I told you so" and laughing at me. I made the switch and haven't looked back. If they keep making engines like this, I never will.

Now if my 170 would ever show up.......LOL

-Mike