[adal]

Can anyone  Please tell me. the type of engine that was put in the Sovereign rotary  44cm 3.75hp  i know it's a briggs and stratton  i need to know the name of it to order some part'I am having fun at the moment it start’s up ok but run’s with low power and the smoke coming out of the exhaust is black I have taking the cylinder head of and found that it is leaking oil past the piston ring’s. I know B&S have quantum – sprint – quarto  i have put a photo of the cylinder head gasket if it will help

[smud6ie]

You can get the engine type from one of the numbers on the engine/casing.there may be some self help on this thread: http://chat.allotment-garden.org/index.php?topic=3345.0
I don't know how much diagnosis you performed before tearing the engine down but black smoke is usally a symptom of an excess of fuel/lack of air and blue smoke of worn rings/bore/vave guides,or did you have a lack of compression/exceesive oil consumption?
smud6ie

[adal]

It was using a lot more of oil than you would normally use.  If you have the piston at TDC and take the piston back it was leaving oil at the top of bore. the house we live in is  on a bank  and cutting the lawn up and down would this have any thing to do with the oil getting past the piston rings. some say you must cut the lawn from side to side if the lawn is on a slant the bore look's ok no there is no  mark's at all .

[smud6ie]

Side to side is the way to go,up and down a bank is dangerous for the operator as well as bad for  the engine,when the head is below the sump,as in going down hill, engine oil leak can  out of the muffler or breather as well as being burnt.
smud6ie