Well its been a while since posting here, and I have eventually managed to get the engine mounted on a test stand......but its not all plain sailing...
AA5BY, firstly to respond to your comment above, I believe that the spring goes in first, and the ball sits in the back of the nipple. Once installed, you can blow INTO the crankcase, but you cannot suck air out the nipple. This kinda makes sense, given that the forcing the PCV closed under pressure, will allow gases to pass into the cam area and up into the valve box. Its a smart system, I like it. But as mentioned by others, over-revving the engine is likely to interrupt that process, with detrimental effect.
So, mounted the engine and put some Stihl HP, mixed 30:1 with 95 pump gas, in the tank. The engine was given to me, and they did not give me the ignition unit, nor was I provided with the pickup sensor. I have installed a standard Rcxel sensor, supposedly for a DLE-61 engine, and the CDI is from an NGH 38.
Hand starting seemed out of the question, and considering there are a lot of 'variables' in the ignition department, I decided to use the Align starter that I have. Its quie a powerful unit, and swings my Saito FG60 without a problem, as well as a Saito FG40 and the NGH38...
I dont have a servo to operate the throttle on the test stand, so just installed the idle stop screw, and got it just off 'closed position'....between the ignition timing and the throttle position, it was a bit of a problem getting it to swing nicely. At one point it would go through one rotation, and then fire (BTDC obviously), and stop it dead! I retarded the timing as much as possible, and managed to get it swinging through multiple revolutions, and eventually it fired. I noticed that there is a LOT of compression on this thing, and if you open the throttle too much, it sucks in even MORE air and the compression goes UP!
It was running at a fast idle but as soon as you try and advance the throttle, it just dies. I opened both needles to 1.5 turns, and fired it up...much better...managed to set the high needle to give me just on 6500rpm on a cheapy 18x10 wide blade prop, which I though was pretty good. Tuned it back to 6350 so its not rich when it unloads. Its very good, but there seems to be something not quite right, the idle is a little erratic, but given that its got new piston, rings, con-rod and bearings, it might take some time to bed in. I also need to go and check the ignition timing again. I have heard the OS ignitions had a weird curve, or they had some trickery built in to the curve. The NGH ignition curve is also apparently a bit odd. So I will try a simple Rcxel unit and see if its any better. Most engines run well on a 28Deg BTDC curve, that is electronically retarded to 4-5 Deg BTDC at starting...this one should be no different.
The carb is also quite sensitive on the needles, and I did have a mid/low-range 'rough or flat spot' which is typical of Walbro carbs, hopefully sorting the timing will allow more accurate tuning to reduce the mid-range stumble.
My FG40, NGH38 are also engines that just DO NOT LIKE hand starting, and expect this one will be the same. Given that I paid nothing for it, forked out $200 to get new parts and have ignition units lying around, it could be a good find...I really dont like the huge muffler, and am reluctant to spend money on a Keleo or Turbo header. I have no flight restrictions and the ideal component would have been an 90Deg Elbow and some of the flex pipe that OS sells, seems like the 16mmx1mm thread might prove difficult to find such an animal...