I'm trying to make a race lawn tractor but the motor is compleity fried, it used to be an accuall lawn mower that mowed lawn but the engine just randomly stopped. It's 15 horsepower don't know what kind of motor though. Thanks can you help me please.

Its hard to give advice , when we don't know what were working on.

Hi,
Cannot tell you except that the USLMRA is at:
United States Lawn Mower Racing Association (http://www.letsmow.com/)
Andinstructions from one source are at:
How to make a racing lawn mower (http://www.instructables.com/id/How-to-make-a-racing-lawn-mower/)
Cannot tell much else with so little info.
Peace,
Clarke