This might be a dumb question but i have to ask. I have a lawnair IV with a 3hp briggs ic engine. This unit is pretty old but it runs and works great. I do not have a manual. The engine has an oil fill spout in the front and back. The gear box also has an oil fill. After i filled the gear box with oil, I checked the engine oil. It appeared to be overfilled because when I opened the plug, oil rushed out like it was under pressure. Is the gear box and engine oil the same? Which oil fill spout do I use to add oil, front of engine, back of engine or the gear box ? The oil fill at the back of the engine does not spew oil when opened. Also, oil was leaking from the drain plug of the gear box and it was pretty tight. Thanks for your help. I'm not going to start it back up until I figure this out.