you could , but you don't want it to flood it and wash the cylinders. you should be ok with a mechanical, just keep it running when it fires, you really don't to be shutting it off before the cam has been broken in. make sure you have no water leaks and use a flame arrestor of some kind. I turn my idle screw up some too, but I also used a running carb that was already tuned. if its right at TDC , you can advance the timing a smidge as well, just to make sure it will run.