I have a craftsman tractor 18hp mo,917.273403 B/S enigne Mo.31p777 type 0299-E1 I'am not a expert on gas enigne But I'am handy with tools and machinery.To make a long story short it was ran with out oil and it stop. My tractor has no more then 100 hours since I purchase it in 2004. I shop around for a replacement it was to costly and to take it to a shop they are so back up that it take a while to get it back and it not cheap to repair. Well I decide it take it apart and this is what I had do, replace the pistion and connecting arm and new rings check the bore and houseing was OK. (no crack) crankshaft wasn't bend (lucky) putting together I made sure that gears dots match.
Now my question when I go to start the engine it just spin and spin, I pull the cap from the spark plug it has light spark, check the timing on the valves, also I could fill some compression, any advice that I have over look. In assembly the enigne.
Thank you
Rich

Use a real compression tester and tell me how many lbs you get while cranking

Hi,
My guess is that it is in tha valves - pushrod not seated.
Peace,
Clarke