Gravely gets wet won't start

i have a Gravely ProStance 36 with a Kawasaki FS600V. I transport it on an open trailer along with my ProStance 48. When it rains my Gravely 36 won't start unless I bump the starter 5-6 times. It eventually starts up normal. If I spray it with a water hose it will do the same thing. I took it to my dealer and they claim it's normal and unavoidable due to the starter design. Same starter as any other FS600V. Has anyone run across this problem?