Don't dismantle the engine just to clean it out of any swarf that might be left behind. Just take off the backplate, glow plug and muffler and sacrifice half a tank of fuel by blasting it in through the exhaust port while aiming at the transfer ports. This should wash an loose stuff out of the transfer ports down into the crankcase. Hold the engine so the bearings are facing up so you don't wash anything into the rear bearing. Then blast more fuel up through the backplate opening to clean out the last bits of rubbish (if any).

The OS instructions are quite complete but assume that a beginner knows what "4 stroking" means. This 4 stroking on a first run isn't just for run-of-the-mill engines either. Both Jett and Profi say to run their pylon engines in a rich 4 stroke for a short time. Harking back to that ultra rich experiment I did, the top half of the rod bush was polishing very nicely while the bottom half still had the original machining marks which basically proved that the piston does [/b]not[/b] jam into the pinch and have to be pulled loose by the rod.

Using a small prop for running in is good advice, I used a 9x6 to run in a 51 size engine, but it's wise to use a fuel with a fair bit of castor, mainly to lubricate the rod ends, which ideally need around 30 minutes of light load running (that's where the small prop comes in) before they've polished completely.

One other tip for running in...use an old plug, especially for the first run, because if any tiny bit of swarf happens to get on the coil then that plug will be dead.