Going to be tearing down this engine, but thought I'd let the experts give their opinion on what could be the problem. Is the link to youtube. I'll be starting with a cold leakdown test first and popping the engine in the van complete as I am convinced there is no major damage to the internals if it is idling OK. Tappets are hydraulic and cam is very mild at only 255 duration. I do not have that single progressive so I will be bolting on a set of Solex PDSIT. From the sounds of it it almost sounds as though the tappets have either failed or the choke was not releasing preventing it from revving up. Let me know your opinions and I'll keep you updated with my progress today.