vj200slens

turns over but wont start doesnt seem to be fireing . seller says it ran fine 3 weeks ago then wouldnt start , (she) had a friend check it and said it needed a p/p .
where do i start in getting this thing started . i would like to buy but really want to test drive it first . it appears to be a very well kept outboard. are there any problems with this model?
whats the approx.$ of the power pack

thanks in advance