I've had this forklift for years and always ran great, now will start run good for about a minute and then start missing to the point where it eventually dies. It will always restart but same problem. I have replaced the vaporizer , mixer, checked the fuel lock, spark plugs,Wires, coil, distributor cap, adjusted the valves, leak down test, the vaporizer is getting hot water in and out of it. Seems to be getting fuel all the way to the mixer, I am at my wits end, any ideas. Thank you.