What is the model number off the mower?
Should be on a sticker somewhere on the deck. Or under the discharge door.
Murray stopped producing the owners manual. I did find a parts breakdown. Also a manual for the engine. Would those be any help?
Yes they would..
http://www.briggsandstratton.com/pdf/owners_manual/100/277039TRI_B-Domestic.pdf Follow this link to a PDF manual for your engine. Here are picture breakdowns for your mower.