Small Engines (Lawn Mowers, etc.): Murray 46, 16hp, Hydrostatic, dana spicer, drive pulley

Question
I cannot find the model # on this mower as I bought it used and the labels are hidden or missing.  It is a Murray 46" with a B&S 16hp and a Dana Spicer 4900-3 Hydrostatic transaxle.  Everything on the mower is working, but my forward and reverse do not have the speed they should.  I still have plenty of torque, but the speed is about half of what it used to be, especially going forward.  The drive belt tension seems to be okay, but I can't tell if the belt is slipping and with no owner's manual I am not sure how to check fluid levels on the transaxle.  Thanks ahead of time for any help you can offer!

Answer
usually we see very few with the fluid levels on the low side. One thing I have found a few times was the engine bolts that hold down the engine from underneath had become loose. Start the engine with the hood up watching carefully of any movement of the engine during start up. Sometimes they become loose, and when they do the engine will shift just a tiny bit, just enough to place less tension on the front drive pulley. Second thing to check is to make sure the idler pulley is in good condition, along with the spring that holds it. It these thing look good, I'd go ahead and replace the drive belt, I have found many that looked good but it doesn't take much for your condition to present itself. Just one other thing to check, make sure there is no where the engine might be leaking oil on to the belt, have seen that a few times too with the B7S engines, either the lower crankshaft gasket on the oil sump pan was leaking, or the sump pan gasket itself.........Tom