Hi guys
Recently done a engine rebuild on a hyster 2.50 lpg Mazda fe engine. It starts and idles perfectly. But seems a bit slow at revving up, but if you show it any kind of incline it wont open out. Ive been over the timing and that checks out fine. The lpg regulator and vaporiser is new. I have tried adjustment s on the carb such and the lean and rich screw but it doesnt seem to change much

Any one have any ideas?