I understand that this is on occasion possible. I looked into it a few weeks ago when I was needing a 120 for my new 110, but the price was only about $125.00 less that I could get in a "combo" deal from Extreme Flight. I opted to just get a new one from EF.
Personally, I am going to go with Terry on this one. If you can afford it and have the time...buy new. However I will say that I have purchased one "nearly" new 3dub from a friend. He has an impeccable reputation and a very trustworthy individual. I don't think you will find a more straight up guy than Joe Mitchel @Flyrcjoe . The 3dub 170 classic I got from him had maaaaybe two or three gallons through her. And he broke her in absolutely perfectly. She is a monster. I also purchased a used 3w 212 for my big Yak. But again, the gentleman has a reputation that preceeds him, so I really haven't been too concerned. My 157cs was brand new as was all my other motors. It is really very difficult to "know" for certain the break in, use and care for things such as motors and electronics. DA has it's advantages like Terry said. If you buy one used and have doubts? Send it to the boys at DA and it will be good to go. On the other hand, a 3w is pretty tough to destroy. They are unbeatable and unmatched for quality and dependability. (in my opinion) Unless you are just plain ignorant and totally abusive, a 3w motor that has been properly broken in and taken care of is a very sound investment that is one class act that is tough to compete with.
I am not absolute authority on tuning, but I can offer what I know has worked for me. Tillotson carbs really aren't too hard to tune once you understand them. Unlike a Walbro or knockoff Walbro, a Tillotson requires "VERY" small adjustments to achieve what others require. A little at a time until you "get" there. Once you've found the sweet spot? Leave it alone. Done.
I believe Cam (Orthobird) has a DA150L and a couple of DA170s for sale. You couldn't ask for a more reputable seller.
