Small Engines (Lawn Mowers, etc.): B&S 17hp model 42A707, crank shaft, head gasket

Question
Ben,

Recently bought a tractor with a B&S 17HP twin model 42A707 type 2238E1 code 4205B. It ran for maybe 10 hours then lost compression in the left bank.  pulled the head to find the intake valve seat had come loose, and there was evidence of the exhaust seat having been loose in the past.  A local repair guy (very helpful) explained how to reaffix the seat peening the alum over with the valve seated, gave me a new head gasket and all was ok for about another 10-15 hours running, then lost compression again.  Pull the head again, same problem...but now the seat seems to be loose even after I peen the alum over,  and the valve no longer seats tight.  Its like the seat is too deep into the block for the valve to seat fully.  The local repair guy says there is nothing that can be done, the motor is not fixable...is there a way to repair this or do they make a deeper, larger valve seat?  thanks for the help

Answer
Tom
First of all it sounds like the crank shaft may be the problem You can reseat the valves again but you will have the same problem. Everything can be fixed one way or another,depends on how much time and money you have to spend. They do not have a replacement engine for this model. All you can do is rebuild/repair WIndividual Parts.