Appealing to the brains trust here once again. The in cockpit throttle lever on my Bukh 24 now fails to accelerate beyond Idle. It is the single lever type where a forward push shifts it into forward gear and further forward push on the lever increases revs. It shifts into gear (forward or reverse) fine but does not accelerate beyond idle. It appears to be a problem with the lever as the single cable does not push the throttle at the engine and it seems to be connected properly at both ends (no loose nuts) but doesn't seem to push from the back of the throttle lever either. A picture of the rear of the throttle lever is attached if anyone is familiar with this type of unit. Any suggestions greatly appreciated.

Sounds like a throttle/acellerator cable disconnect of some kind.
Were it me which it ain't, I would:-
1. Disconnect the inner cable from the engine lever, start the engine then attempt to acellerate the engine out of gear to confirm that the lever is securely clamped to the injector pump control shaft. If that proves, proceed to :-
2. Still disconnected, engine stopped, confirm that both ends of the outer cable are properly secured. That proven:-
3. Work the cockpit lever through it's range to confirm the inner cable is not broken. That proven:-
4. Recheck the cockpit mechanism through it's range. That proven:-
5. The indication is that there is an internal fault with the injector pump, in which case, hire a professional.
As with most things it is a process of elimation to identify the fault.
Let us know what you come up with.
Sounds like a throttle/acellerator cable disconnect of some kind.
Were it me which it ain't, I would:-
1. Disconnect the inner cable from the engine lever, start the engine then attempt to acellerate the engine out of gear to confirm that the lever is securely clamped to the injector pump control shaft. If that proves, proceed to :-
2. Still disconnected, engine stopped, confirm that both ends of the outer cable are properly secured. That proven:-
3. Work the cockpit lever through it's range to confirm the inner cable is not broken. That proven:-
4. Recheck the cockpit mechanism through it's range. That proven:-
5. The indication is that there is an internal fault with the injector pump, in which case, hire a professional.
As with most things it is a process of elimation to identify the fault.
Let us know what you come up with.
Thank you very much for that. I'm going to have a go at it tomorrow because I didn't have the time on Monday so that is a very helpful clarification for my process. I'm hoping that it is not something to do with that alloy plate at the top which seems to slide up and down relative to the rest of the mechanism and carrying one bellcrank with it but which doesn't seem to have any exposed mechanism. Strangely there also seem to be electrical connectors for a spade connection which aren't connected to anything but that is probably another issue.
So I had a go at this today for quite a long time and the cable is not snapped but I need to remove the lever to properly examine the mechanism on the inside because the access on the inside is absolutely terrible. A picture of the lever is attached in case anyone has the same one. The plastic square on the pivot axis pops out to reveal a large screw which I also removed but despite tapping the lever with a hammer on all sides as hard as I dared and prising outwards with a large screwdriver I could not get the lever to come off. It may well be corroded on. Does anyone know if it should come off in this manner so that I can pull the inside away from the bulkhead and dismantle it? thanks in advance.

Check that the outer sheath of the cable is secured and is not moving back and forth with the inner cable