How to repair diesel made in china?

I paid £500 for a marksman diesel generator,Its a electric start it has 230v and 110v the 110v seems to work but the 230 dont work,i have only used 2 times Ileft it with a small machine engineer he could not find any info on it or repair it.So im left with a generator thats not any use,I have heard dont buy anything made in china [it looks pretty] can any body help thanks.