Going to Pages > Tech, or Pages > FAQ will be helpful. Search has been occasionally having issues recently but if you click on the search button without anything in it, it will take you to the search where you can search for your questions. Just about everything you can imagine has been discussed including what parts to buy and not buy.
Do you know what is wrong with the motor? If it will turn but not start, you could do a compression check to get a baseline of motor condition.