I have a gleaner e3 and they used two different engines in them and use different oil filters and the book says not to mix them up. I can't find out how to get the serial number off the engine. Does anyone know where to find the id. I must have the right oil filter thats on there now but I'd like to know for sure. Other question is how are you supposed to get to the carb. is there a better way or a best way. I'm not that nimble any more. One more question The engine runs hot and sometimes I can see little air bubbles in the rad.(but not always) So I did a compression check and they are 150. 145, 140, 150 (cold) The plugs look good but #3 is a little black others are white/tan and clean. could it be a head gasket?