Hi guys this is my first time on rc tech so please bear with me here goes.

I bought a revo last week has a picco 26 max engine nova cooling head the guy bought the engine last summer and has had a 1/4 gallon throgh it. I've had the engine running about and it cut out on me. The engine wouldn't turn so put some afteroil in still no joy. I then took the engine off the mount taken the cooling head to reveal the piston i then tried my roto start on it the piston was moving freely i sprayed with wd40 to clean for best measure and put the engine back connected the exhaust,air filter and glow plug and engine still wont turn i had to push the fly wheel with my hand hard to unlock. tried loosening the glow still no joy. the engine will turn with the glow plug out though. but as soon as i make the slightest turn it stops.

PLEASE HELP IM OUT OF IDEAS I KNOW NEW ENGINES ARE TIGHT IVE TRIED PRIMING, USING HEAT GUN ETC