914 bought – small problems

I’m still completely inexperienced in terms of trucks and hope you can help me: 1. Starter problem The starter engine sounds like it’s turning, but rather creaking – the engine itself doesn’t turn. After some start-up attempts everything sounds “normal” and the engine is there immediately. I changed the magnetic switch (a cheap product) – but it didn’t work. 2. Motor brake I assume that the switch to turn off the engine while driving as motor brake fungie Rt. If I press it, the engine no longer delivers power and smokes black out of the exhaust. Put it off and restart (with the above problem) so far (twice tried) remedy. 3. Part without function On the right side of the engine (gear side) a 20 cm long and approx. 4 cm wide round part perpendicular to the engine is attached. At the top a thin hose can probably be flanged – here the opening is open. An appropriate plastic hose hangs loosely in the vicinity. Um – but its opening is mechanically closed. Does all this mean?? Maybe you can help me. P.S: Is there a workshop manual somewhere?? The operating instructions are a bit poor. Thanks in advance Matthias