about the best you can do without a meter is line the timing marks back up on the pump to the housing. it will most likely not be dialed in but will get you close to run to the shop. you can play with the timing by ear but even seasoned guys can only get to within a deg or two doing this. thats the only drawback on these simple engines, it takes some special equipment to time them properly.
btw, do not remove the housing to get the pump off! take the front cover off and remove the three bolts and slide the pump out the back of the cover. this keeps the timing gear in alignment, if you pull the gear cover that is held by two bolts apart you will be pulling the front of your engine off to get it all lined back up.