Small Engines (Lawn Mowers, etc.): Push lawn mower, aluminum decks, white smoke

Question
I have a self-propelled Murray lawn mower circa 1980.  I just got it out of the shop for yearly maintenance and it ran fine.  After cutting average height/thickness grass my son noticed it was blowing white smoke and had blown oil out of the exhaust.  I understand that the gasket is probably blown.  My question is do I have this repaired, ot is it time to get a new mower.  I have app 3/4 acre to mow.  If it's time to buy can you tell me how to decide what new mower to buy?

Thanks SO much!

Answer
 Hello Linda:

 I would say at 26 yrs Old and having to Mow that much Grass. Yes, Purchase a New Mower. Little things May soon Start Happening to it and in the End you will have Spent as Much for Repairs as to Purchase a New One. As for My Choice: I Prefer Honda or Briggs Engines and Aluminum Decks. The Honda is Usually more Expensive, but is Worth the Extra. Hope this Helps.

 Good Luck

 Respectfully

 John