Thank you gentlemen.

I found this site with links to various sngines:

http://www.smallenginesuppliers.com/html/engine-specs/tecumseh-engine-specs.html

And this for a drawing of my engine:

http://www.smallenginesuppliers.com/html/engine-specs/tecumseh/h30-35.html

BTW, the reason I initially could not adjust the reel down to the sole plate, was the fact that I didn't realise the little locking nuts needed to be loosened and that the two adjusting screws have to be turned in opposing directions to lower the reel. The link you provided helped enormously.

Dave

Reel Mowers do it better.