Thanks Fred
Seized up??
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andrewslarge
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I have a John Deer that just stopped running. I thought the engine was locked up but I was wrong. It was the clutch that was locked up. Replaced clutch and it’s still running today.
The clutch has two bearings. One is in the pulley so it can stop what every it is driving. The other is in the stationary housing This bearing centers the clutch and allows the crank to turn without turning the housing and tearing off the electric feed to the clutch coil.
If the second bearing locks up it will either stop the engine or tear the antirotation device off the tractor which also tears the wires up.
You have a few areas that can lock up an engine,
External.
1. electric clutch
2 magnets came loose inside the flywheel wedging between the flywheel and the stator coil.
3 Ignition magnet came off the flywheel and locked against the ignition coil
Internal
1 a main bearing seized
2 a rod bearing seized -- usually the rod will break and open an inspection hole in the block
3 a piston seized in the bore
4 a valve dropped and the piston hit it breaking and expanding the piston.
There may be other things that would lock an engine but these are the most often causes.
You said there was no noise or other sign of a fault. Allow me to tell a story of my time as a service person.
A tractor with a twin cylinder engine came in for a tune up. The customer said it has been running ok but lately seems to be low power. So we began the tune up and noticed one plug was wet and firing. Stuck a screw driver in the plug hole turned the flywheel and the piston did not move. Asked the customer if he had heard any noise or felt any different vibration and he replied "No, it just doesn't seem to have the power it used to". With his ok I tore the engine down and found one broken connecting rod and an inspection hole in the block.
If the second bearing locks up it will either stop the engine or tear the antirotation device off the tractor which also tears the wires up.
You have a few areas that can lock up an engine,
External.
1. electric clutch
2 magnets came loose inside the flywheel wedging between the flywheel and the stator coil.
3 Ignition magnet came off the flywheel and locked against the ignition coil
Internal
1 a main bearing seized
2 a rod bearing seized -- usually the rod will break and open an inspection hole in the block
3 a piston seized in the bore
4 a valve dropped and the piston hit it breaking and expanding the piston.
There may be other things that would lock an engine but these are the most often causes.
You said there was no noise or other sign of a fault. Allow me to tell a story of my time as a service person.
A tractor with a twin cylinder engine came in for a tune up. The customer said it has been running ok but lately seems to be low power. So we began the tune up and noticed one plug was wet and firing. Stuck a screw driver in the plug hole turned the flywheel and the piston did not move. Asked the customer if he had heard any noise or felt any different vibration and he replied "No, it just doesn't seem to have the power it used to". With his ok I tore the engine down and found one broken connecting rod and an inspection hole in the block.
I think you're jumping the gun with an engine diagram. First, determine what's is obvious as being wrong and go from there. Once you see damage, then you'll figure wither you want to tear the whole engine apart, or not.
Remove the spark plug, try rocking the flywheel back and forth and watch the whole PTO clutch to see if only the top is rocking, or top, bottom and deck belt. If everything is rocking, the clutch may be frozen. Unplug the clutch cable and remove the anti-rotation bracket, or pin. If you can rotate it now, going slow, then you should remove the clutch and the upper pulleys. At his point you could install the plug and try with the starter. Maybe even starting.
If the clutch is not frozen, remove the valve cover and inspect the push rods for being in place and check the looseness of the rockers. You may have a rod out and\or bent. If all this looks good, you should remove the head, but you won't see much. At this point, it's probable internal, like a broken piston push rod or even more.
Now is when you will decide wither to continue, or not. If you continue, you'll need to have the parts breakdown and figure out what's needed and it's price. If may be more feasible to find a replacement used motor. That engine type is readily found for a descent price.
Remove the spark plug, try rocking the flywheel back and forth and watch the whole PTO clutch to see if only the top is rocking, or top, bottom and deck belt. If everything is rocking, the clutch may be frozen. Unplug the clutch cable and remove the anti-rotation bracket, or pin. If you can rotate it now, going slow, then you should remove the clutch and the upper pulleys. At his point you could install the plug and try with the starter. Maybe even starting.
If the clutch is not frozen, remove the valve cover and inspect the push rods for being in place and check the looseness of the rockers. You may have a rod out and\or bent. If all this looks good, you should remove the head, but you won't see much. At this point, it's probable internal, like a broken piston push rod or even more.
Now is when you will decide wither to continue, or not. If you continue, you'll need to have the parts breakdown and figure out what's needed and it's price. If may be more feasible to find a replacement used motor. That engine type is readily found for a descent price.
grumpyunk
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Has anyone checked the oil level in the sump? Remove the filler neck cap, wipe clean, place cap on the filler. Remove cap and inspect oil level. If no oil showing, odds are not in your favor of a pleasant surprise outcome.
Removing the cooling shrouds will make access to the flywheel easier so you can manually attempt to rotate the crankshaft while poking around with the electric clutch. I think I would also remove the spark plug wire, and maybe the spark plug, too.
Just because.
tom
Removing the cooling shrouds will make access to the flywheel easier so you can manually attempt to rotate the crankshaft while poking around with the electric clutch. I think I would also remove the spark plug wire, and maybe the spark plug, too.
Just because.
tom
DinosaurMike
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I know nothing about the engine, but do want to say that I am incredibly impressed by the shop owners who take the time to read about people's plights and offer great suggestions and information.