should or keep it the same?

[cosworth34677]

OK i got the excavator I've been workings on for about 6 mouths, everything works but the it has no power, i refurbed the pump new valve rebuilt the cylinders, and tried about 15 different typed of oils anti freeze bake and power steering fluid. and it moves well not fast but well. i'm about at the point where going to just pack everything up and sell the whole lump. so.......

so should i sell it? keep working with it?
or sell the hydraulic stuff and go screw drive cylinders?
help guys!!! i was also thing of sell the hydraulic system and using the money
to fund a new one but really if i sell the parts that will turn into bill money.
what would you guys do? i'm about over spending money on this thing with no gains!! help!!