I just got my 8th flight on a new YS .63 and now it seems to have gone all wrong. The plane lost power on the last flight and deadsticked on the last three. I've adjusted the top end but have a detonation problem now. Is there a good starting point for the low end adjustment? I know the manual says 2 1/2 turns for the top end and YS says 2 but nobody ever mentions the low end. Also any adjustments necessary to the boost valve. I plan to reset the rocker arms today and reset the entire engine and would like some good starting points. I'm using YS 20-20 fuel with an APC 13x4W prop and it seems to work great. Any Ideas?? Thanks a million.

Go to www.ysperformance.com and follow the running instructions, but before you do, reset both the valves to .003"

I have those printed and in hand. I use a .003" shim to adjust the valves on all of my engines. I'm hoping these are out of adjustment when I check them as the engine seemed to change performance drastically and that would be the easy fix. Just got my other .63 back from Richard and it runs like a dream. It's back in the CAP and flying today.

I hope that this one doesn't also have to come back, too. One other thing, is the engine leaking fuel out the carb with the tank pressurized? If so there might be some crap in the reg.

I checked the rockers and used the tune up info from your web site and the engine ran beautifully. Flew it three times today between flying the CAP three times. Both were great with plenty of power. I'm sure the first one was just a fluke. Looked like a bad casting to me. It happens. I'm a toolmaker for the DOD so I understand metal and metal processes. An occassional bad casting is quite normal. The important part was that they fixed it and got it back to me quickly and under warranty. I'll check the regulator as fuel does occassionally come out of the carb but there is a filter between it and the fuel source. Thanks again!

10-4 to the casting deal. We've seen a few with fatal flaws over the years.

As far as the carb drip goes, sometimes they never do seal up completely. The problem comes about when they stop dripping and start GUSHING. At that point they will not idle and will sometimes not transition but the top end is fine if you can get there. It makes power on landings a little tough, though.

Well I evidently don't have a problem then because right now both engines transition beautifully. Good information for the future and to share around the club though. No one seems to know much about these engines except that they put out great power and they like them. Anyone with a .60 size 3D that isn't flying a YS is under powered compared to our planes. That's not only an opinion but an observation. I'm sure the rest of the sizes are the same as the really serious 3D guys in our club are flying with YS regardless of size. Of course the real pros in the club are flying DA 150s but they still use YS on their small scale. Great product if you want raw power for 3D.

Good Flying!