I've got a riding mower with a Briggs and Stratton 14.5 HP engine. It froze up the other day when my daughter was mowing. I suspected that she'd let it run out of oil. The oil was really low, so I filled it up. I managed to get the engine to free up, but there seems to be something that stops it from turning freely. I turn it by hand and it turns until it appears to hit something and then won't turn any more in that direction. I've got the blade pulley disengaged, so that's not the problem.
Seriously, you probably siezed the piston rings, and the cylinder wall has a groove or ridge. My father did that once with a 3.5 HP briggs. I took the head off and pounded the piston down with a brass hammer. Then i greased the piss out of the cylinder walls and spun the blade until it spun easily. There was a noticable groove in the cylinder wall, but I put the head back on it, and it started. It smoked pretty much at first, but an hour later it ran good and the smoke was minimal. This happened about 15 years ago. I now have that mower, and it still runs.
I'd start by pouring a little oil in the spark plug hole. Leave the spark plug off the engine, and spin the engine with the blade. When you get to the tight spot, work it back and forth, and add more oil. Flip the whole mower over for a second to get the oil to the bottom of the cylinder too.
If you cant loosen it up that way, I'd tear off the head, look at the cylinder wall. Actyually, the best would be to pull off the pan too. You could also have a scored rod bearing, or a bent lifter rod, or who knows what else. Those 11 and higher HP engines are notorious for having the rod bearings go bad. I had one that just blew the whole engine apart. Mine occurred because the pan bolts came loose from vibration, and all the oil dumped out within a few minutes. The next thing I knew, the mower sropped and there was a chunk of the block laying on the lawn. The entire rod was blown to shreads inside the engine. I had to replace the whole engine. Mine was the 11HP.
So, if I were you, I think I'd check the bearings. A new bearing, and or rod is cheap, but a crankshart is half the price of a new engine. Add to that the cost of a new block, and you may as well but a whole engine.
when i ran out of oil in my toro mower about 25 yrs. ago.. the engine would move but not start.. the reason is that when you pull the rope the crank would move but the crankshaft was broken and it just stayed there... you probably have a broken piston rod and it is hitting the crank when you move it.... one way to find out is to remove the spark plug and then try to start it and if you feel no pressure you know that the piston is not moving....
I wanna see him flip the whole mower over... he said it's a riding mower.... lol
seriously... without seeingi t, it would be impossible to say what the problem is, since every motor will will behave differently when run out of oil. Some might just sieze up the rings as yours did... some might throw a rod, etc...
You happen to have been lucky and got yours to work without putting a lot into it, but most aren't so lucky.
I have yet to see a riding mower engine seize in the piston rings. The connecting rod/crankshaft journal is usually the first thing to go, occasionally the top main bearing if it is a vertical shaft engine.
Sometimes the crankshaft can be salvaged, cleaned up. A nasty deposit of aluminum connecting rod on the rod throw is a good sign, throw is less likely to be scored then. New rod, $15 Stens or Maple Grove, $25 - $30 from B&S. Turn Crankshaft, if needed, in this local, $35. Gaskets, seals, rings, another $25 - $35 depending on where you get them. May want to check your local NAPA Store.
To find out how to easily clean aluminum rod deposit from crank throw, snipped-for-privacy@onemain.com
Walt Conner
just sieze up the rings as yours >did... some might throw a rod, etc...
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.