need help identifying a k series kohler engine

[Martin 2,132]

what type of muffler has a 1 1/4 id and where can I buy one

heres one at napa.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=SME703676_0215388129

[seth0804 5]

Yes I agree, but the engine should run off of the regulator at full throttle as least and it does not. Thus the battery won't charge up and then die and will not start up again. Right?