Small Engines (Lawn Mowers, etc.): heater, 4 quarts, dipstick heater

Question
 Hi Eric!  My lawn tractor won't start on cold days.  Could you advise some good flexible dipstick heaters?
Thanks,
      Seth

Answer
Found a block heater on this link:

http://www4.briggsandstratton.com/miscpdfs/RNT/Accessory%20Catalog%20ms3880.pdf

BLOCK HEATERS
Part No. Models
699312 12 (after date code 020417XX)
SNOW BLOWER EQUIPMENT
Part No. Models
699358 20/21

Not too sure if they will fit your old engine but worth looking into.

Eric