08 honda420cc 4x4 engine problems?

I have a 08 Honda 420cc 4x4. Same as this http://www.google.com/imgres?q=honda+420cc&hl=en&biw=1092&bih=533&gbv=2&tbm=isch&tbnid=CMSYG09li6pVEM:&imgrefurl=http://www.atvriders.com/atvreviews/honda2009-rancher-420-at-es-utility-atv-irs-eps-ride-review.html&docid=gPCB4LO7lC0nhM&imgurl=http://www.atvriders.com/images/honda/honda-2009-rancher-at-es-eps-irs-utility-atv-review/honda-rancher-420-es-at-eps-irs-utility-atv.jpg&w=1024&h=614&ei=COp4T7G_DMfNhAezr92cDQ&zoom=1&iact=hc&vpx=103&vpy=169&dur=281&hovh=174&hovw=290&tx=225&ty=69&sig=110277983229558157555&page=1&tbnh=129&tbnw=215&start=0&ndsp=8&ved=1t:429,r:0,s:0. (sorry for long link!) Anyway I parked the quad two days ago after using it for less than half an hour and it was left idle for about 15 minutes! I did went to start it and there was a clicking sound coming from under the seat! I put the quad into netural still no luck! I then started pushing the quad back and forward and it started! This was ok for a day and the same problem happened again and again I shook the quad back and forward and the engine started! That was ok until today when I started the quad today and it started ok but it was like the engine was dry or something but it wan't a smooth start. This happened the whole day and low and behold tonight the problem elasticated! I was up seeing sheep that were near lambing and I turned off the quad and I had the same problem starting it but I shaked it and it started. I then tried to move up gear and I couldn't so I had to go in first gear all the way home! I can't reverse it or change gear up or down. The quad has petrol and I gave it a through service during the winter and she was working perfectly!! Does anyone know what this problem is? Is it major or a quick fix because I need the quad daily! Any advice would be great!!! Thanks everyone