Andy,
Not sure if you read a few postings back about getting a ROPS for you Yanmar. It's a life saver - literally. Fredricks has a bunch of them that fit all of our Yanmars and CUT John Deeres at a very attractive price. It's more than just the foldable type, it has seat belts and the PTO shield setup. Find the ROPS that fits your Yanmar here:
ROPS Manuals Fredricks Importing right down to the detailed drawings and mounting!
If any ROPS is still outside your ability to afford, then do quick search and find the National ROPS Rebate program for homesteaders and farmers. It will reduce the price by 70%.
The other thing a ROPS is hand for ... A sun shade mount, lighting mount, behind the seat tool carry-all bin, mount the SMV sign, a place for the up-holder.

I've attached my ROPS info pix on the YM2610 ...
Another hand item to have are the front weights. The Yanmar CUT weights are identical to the John Deere because Yanmar supplies them. JD in green, Yanmar in black. Not sure why black and not pale green or Yanmar red. I've looked around and the majority were black.
Lowes has them for $64 each with FREE shipping to the local store of your choice. Unless you find a CL deal, it's hard to find these used at a lesser price. If I ever get time, it would be nice to make a 2D drawing of the mountable weight and make a simple frame mold to make these out of concrete.

Of course concrete density for 20Kg is a larger size, so maybe using FreeCAD v17, I do a 3D model and adjust the size to match. hmmm.
FreeCAD: Your own 3D parametric modeler
You got a nice machine. A head gasket isn't too hard to change out, just a bit of time really.