I have changed everything and still have that problem! It runs, quits, sputters and bogs down. If you can keep it going it'll run fine at high speeds when driving it, but uses a lot of fuel and a strong odor of gas. I cant figure it out! No help from Massimo and I've made several calls and sent e-mails! Also had it in 3 separate shops, to no help! Still runs the same! It overheated once when a water hose worked loose, but not to the point of hurting the engine. The only thing that's ever happened to it, up till this running issue! I could use some help too and you aren't alone.