I got an MTD mower from a friend and the engine does not have the original shroud on it so I dont have a model number. is there any other way to tell what model engine I have so I can buy parts for it. I have reason to believe that it is either a 14.5HP OHV IC or a 16HP OHV IC and not the 18HP that the shroud says because the breather is different. any help I can get will be greatly appreciated.