My friend has three motors that the casing does not give a clue as to their size.We would like to find out approx. age, and size and if parts can be gotten for them and possibly books for mixture of gas and type of lubricants for the bottom assembly.<br /><br />The first has a lever to take out of gear and the only numbers found on the motor are stamped in the block. Seems to run very well and would like to keep that way. ser 851658<br /> mod TN 26<br /><br />The second is the same appearant size but without the out of gear lever. Does not appear to have a water pump but haven't checked real close. ser 541891<br /> mod HD 25<br /><br />The third is much smaller with no lever. Does not appear to have a water pump but haven't checked real close. ser 680628<br /> mod TD 20