Let me say up front, I am an amateur. I like to rebuild small engines strictly as a hobby and I am still learning.
I got my hands on an old Merry Tiller with a 3.5 hp Briggs model 92502. I can't give you anything on the engine code, serial number or date stamp beyond that because someone at sometime removed a portion of the housing just after the model number. It has a pusla jet carb with the front pull out manual slide choke and the small pickup bowl in the tank so it has the two down tubes. I took the carb off and did a complete breakdown and made sure ALL of the ports were clear. I've redone a number of Briggs carbs so I know where all the small holes and ports are, even the two small holes under the needle valve seat. I'm confident I cleared all of the ports. I put in a new diaphragm and replaced all the gaskets. I mounted it back to the tank securely. I connected all the linkages. I set the needle valve at a turn and a half back from closed.
I had replaced the exhaust pipe. I thoroughly cleaned the tank inside and out. I removed the flywheel and removed all the rust from the flywheel and the magneto. I cleaned the contacts on the magneto. I removed the cylinder head. There was a lot of carbon that I cleaned off the valves and cylinder head. I cleaned the valves with a wire brush and some very fine sandpaper. The valves appeared to be in very good condition so I did not lap them. Both valves seemed to close well, the exhaust valve closed tight and I could not move it with my fingers when it was closed. I noticed that although the intake valve appeared to close well and tight, I could turn it with my thumb in the closed position. The cylinder head was in excellent condition once cleaned and the cylinder walls were perfect, no scratches or scoring. I opted not to remove the crankcase cover. I flushed the crankcase and added fresh oil. I replaced the head gasket and closed it up. I replaced the spark plug and checked it for spark before I put it in and it was sparking well when I turn the engine over. So I buttoned everything up and tried to crank it but it's not turning over. I took the carb off and did a second cleaning and inspection but same problem. I tried a little starter fluid in through the carb but nothing. I tried a little gas directly into the spark plug opening but nothing. It has very good compression. When I took the plug out it was not overwhelmed with fuel odor so it does not seem to be flooded and I even considered whether it was getting fuel but since it wouldn't turn over with gas directly into the chamber I thought that probably wasn't the problem.
The only thing that stick out to me is the intake valve needs to be lapped but I didn't think this would completely prevent the engine from turning over. What am I missing? Suggestions, thoughts and ideas would be greatly appreciated!
I can attach pics if need be but I didn't know what would be helpful at this point.
I got my hands on an old Merry Tiller with a 3.5 hp Briggs model 92502. I can't give you anything on the engine code, serial number or date stamp beyond that because someone at sometime removed a portion of the housing just after the model number. It has a pusla jet carb with the front pull out manual slide choke and the small pickup bowl in the tank so it has the two down tubes. I took the carb off and did a complete breakdown and made sure ALL of the ports were clear. I've redone a number of Briggs carbs so I know where all the small holes and ports are, even the two small holes under the needle valve seat. I'm confident I cleared all of the ports. I put in a new diaphragm and replaced all the gaskets. I mounted it back to the tank securely. I connected all the linkages. I set the needle valve at a turn and a half back from closed.
I had replaced the exhaust pipe. I thoroughly cleaned the tank inside and out. I removed the flywheel and removed all the rust from the flywheel and the magneto. I cleaned the contacts on the magneto. I removed the cylinder head. There was a lot of carbon that I cleaned off the valves and cylinder head. I cleaned the valves with a wire brush and some very fine sandpaper. The valves appeared to be in very good condition so I did not lap them. Both valves seemed to close well, the exhaust valve closed tight and I could not move it with my fingers when it was closed. I noticed that although the intake valve appeared to close well and tight, I could turn it with my thumb in the closed position. The cylinder head was in excellent condition once cleaned and the cylinder walls were perfect, no scratches or scoring. I opted not to remove the crankcase cover. I flushed the crankcase and added fresh oil. I replaced the head gasket and closed it up. I replaced the spark plug and checked it for spark before I put it in and it was sparking well when I turn the engine over. So I buttoned everything up and tried to crank it but it's not turning over. I took the carb off and did a second cleaning and inspection but same problem. I tried a little starter fluid in through the carb but nothing. I tried a little gas directly into the spark plug opening but nothing. It has very good compression. When I took the plug out it was not overwhelmed with fuel odor so it does not seem to be flooded and I even considered whether it was getting fuel but since it wouldn't turn over with gas directly into the chamber I thought that probably wasn't the problem.
The only thing that stick out to me is the intake valve needs to be lapped but I didn't think this would completely prevent the engine from turning over. What am I missing? Suggestions, thoughts and ideas would be greatly appreciated!
I can attach pics if need be but I didn't know what would be helpful at this point.