Can a lawn mower work as a kayak motor? Can anything bad happen?

the motor will be in the water and i am using a 12 volt 18 amp battery
here is a link to my lawn mower http://www.amazon.com/Black-Decker-GH710-GrassHog-Dual-Line/dp/B004A871GY/ref=sr_1_2?ie=UTF8&qid=1407104513&sr=8-2&keywords=grasshog+black+and+decker

Other answer:

Elisey Chuprakov:
Will last about five minutes!
Util you submerge the motor!
If you have to have a electric motor buy a purpose made one or just don't bother!
fuzzy:
may well work for a few minutes but I SERIOUSLY doubt that is waterproof enough to live longer than that.
Better ,cheaper healthier & more reliable to lean to use a paddle properly – it's not hard 5 year olds can do it
Sailor:
Agree with all the comments given so far. If it were to work however, there is but one positive advantage, you would have a beautifully mowed lawn on the fore deck.
?:
If you have to have a electric motor buy a purpose made one or just don't bother!
Harry Buttcrack:
RPS is being generous- I doubt it will last 30 seconds. These motors are NOT designed for submersion.
Elisey Chuprakov:
thank you all for your sugestions but i tested it and it worked fine and i have used it 5 times already and nothing broke and it worked for other an hour (untill the battery died)
?:
, there is but one positive advantage, you would have a beautifully mowed lawn on the fore deck.
John Alden:
Your idea is preposterous.