No need to appologise
Just so we know where we each stand
In many cases when a factory makes mowers for some one else then the IP belongs to the original customer so has to be accessed through the MF network in your case.
Now working on the teach a man to fish principle, the first thing to do is find which model Simplicity your mower was a derrivative of
For that I go to
tractor data and look for a Simplicity that has a 25 HP engine, then check the engine details to see which ones were horizontal shafted
From there we now know that you are looking at a rebadged Simplicity Legacy ( probably XL )
Armed with that knowledge then it is off to
parts tree to get a scrolling list of the Legacy tractors and scrolling down to find a 25 Hp Kohler engine with a deck of your size ( not devulged by you ) and from that use the model number shown in the drop down list to go back to Simplicity's web page
All well and good except Simplicity only show owners manuals ( in 5 languages ) & an IPL in english .
But from there we now find that the hydraulic pump is an Eaton item & the wheel motors were Tecumseh - Peerless.
So the service information for them will come from Eaton or Tecumseh not from Simplicity , this is SOP for just about every maker except JD & Toro
The hydraulic pump should have an Eatons model number on it so that is what will be needed to access service information on it .
You could go right through the Parts tree list to find a Legacy with your engine size & deck size made in the same year then approach Simplicity for service information on that model Legacy mower ( don't tell them it is branded MF )
Some Eatons manuals are available on line
This is the best I can do for you without charging .
As there are more Legacys around you might like to try asking forums for service info on what ever Legacy model you identify your MF as .