Motorraum: Heavy starter + limp mode

[Erlingur]

Hello Freunde,

Ich können kaum in Deutsch schreiben deshalb ich hoffe Sie können mich in Englisch helfen

I have en 750 '91
I replaced my starter few months ago, the old one was just kaput.
Shortly after that the starter was extreamly heavy when I was starting, just like the battery was low it was old any way. I replaced the battery but the problem was still there.
It has happened that sometimes when I start the car everything is OK. But not any more. If I use a help from a jump start I can sometimes get the car running, but with some electircal smell and smoke from my NEW starter :(
If I get the car running he usually gets in limp mode shortly after the motor gets started.
There comes no EML light in my dash board and my engine runs very smooth in its limp mode

What can I do?
Could the new starter been kaput?
What is with the limp mode of my engine?

If you have some ideas for me I would be extreamly happy, but maby I have to replace the starter agin, that is not an easy job

Mit freundliche Grusse aus Island,
E