Merry Tiller - Clinton Engine Query

Following the sad demise of my Mountfield M1, with the tie bar sheared off within the worm gear casing, which I am currently unable to fix, I bought a cheap early Wolseley Merry Tiller on Ebay to tide me over.

It's an early model (estimate early '60s), serial number P13634, with a Clinton engine. I've been unable to find out much about it but assume the 'P' refers to 'Professional', and therefore the Clinton engine is a 3 1/4 HP. If anyone can tell me more I'd be grateful.

I've not got it running yet, though the seller assured me it would, but there seems to be something 'not quite right' with the throttle linkage. If anybody has a similar model & can perhaps send a piccy, or perhaps has the appropriate service manual that might show it in detail, that would be appreciated 

A spring is also attached to the butterfly lever at one end and to an arm on a sliding square section rod at the other. Another arm on the rod sticks out for the throttle cable to attach to.

RT - many thanks for your reply. The above description certainly fits the bill - I couldn't have described it better myself. But as for the butterfly lever attached to the governor by a wire link? - there's another spring on the front of the butterfly lever (closest to the inlet manifold) that doesn't seem to attach to anything - although the exhaust is missing, having completely rotted away - and I can't figure out what else it might attach to. Can you advise? Any idea where I might get a replacement exhaust for this model? I've been scanning Ebay but so far without success, though I don't suppose an exhaust is critical - I can always use earplugs