JD D100 Will Not Start

[Scrubcadet10]

What are you torquing the flywheel nut to?

 

[100 td]

I note some things I would do, but from a safety aspect, you should refrain from the following and allow a professional to do your repairs. From your first post, it appears everything was basically good, except that the mower stopped, get back to original and check one thing at a time.It appears that some basic checks may not have happened before tearing down and changing things. No worries, I would just try to get back to original and check one thing at a time.

As previously noted, there is a possibility that the flywheel has been incorrectly installed or torqued incorrectly and has slipped/sheared. A backfire can shear a key at any time, especially if it wasn't replaced or torqued correctly. Clean/fine sand paper the flywheel and shaft with 1000~2000 wet/dry.
Remove key, install flywheel without key, make sure it is set down evenly and doesn't wobble, do up flywheel nut, torque to spec 100 lb-ft (use a tension wrench), measure the length of the thread protruding past the nut with a vernier, also mark/scribe a line from the nut to the flywheel, undo, remove flywheel, place key in-situ, replace flywheel/key, ensure even and no wobble, tension nut and check with vernier that it is the same, and check scribe mark. Many times a key may hold up the flywheel by a tiny amount, it is the mating surfaces of the taper that do the holding, not the key, the key is only a locating/alignment device, and it's generally made of aluminum so that it shears if the forces on the mating surfaces are too great, and can be easily replaced without damage to shaft or flywheel.

Put the ORIGINAL ignition coil back on and set air gap 10 to 14 thousandths of an inch. (use feeler gauges)

Carefully check all wiring for any rub through that may blow the fuse (entire mower wiring harness)

Turn off any ancillaries on the mower, headlights, blade clutches etc.

Slow charge the battery overnight so it is fully charged before you start any investigations again.

Check oil level, if it is over full, completely drain oil and replace with new oil to correct level. If it is low, either top up, or drain /replace to correct level.

If your model has the fuel tank above the carby and uses gravity flow, remove bowl and turn fuel on and ensure good flow, then carefully use a pencil or other apparatus to lightly lift the float to ensure easy fuel shut off. If fuel is low and uses a fuel pump, run a fuel hose from a small bottle above to do the same test. If fuel shut off is not accomplished with very light pressure on float at approx horizontal position, replace needle.
As you have stated you have a fuel flooding issue, ensure the previous step is carried out thoroughly. Also, if you have a crankcase/differential/electric pressure driven fuel pump, disconnect the fuel supply going to it, and from it and rig up a gravity feed fuel supply to the carby for testing/running until engine running is sorted. This gets rid of fuel pressure and also possible fuel leakage past the diaphragm into the crankcase or intake or where-ever this pump is plumbed to.

Ensure no flammables in work area. Ensure no fuel, liquid or vapor leaks in general area. All testing to be done in a wide open outside area with approiate safety/fire extinguishers etc.. First engine test, no air cleaner, fuel tap off if it has one, gravity fed fuel, remove spark plug, plug spark plug into high tension lead and ground the plug well away from the plug hole, well away from the carby, open throttle wide, but not so that choke flap closes, crank engine and check for spark, crank for 10 SECONDS and check that spark stops when key is turned off and engine is still spinning.
Replace spark plug into plug hole, tension to 180 lb-in.
Plug high tension lead onto spark plug. Turn on fuel, allow 30 seconds, manually engage choke or ensure choke lever has engaged at full throttle, crank engine for 5 seconds, or less if it fires. If it doesn't fire, dis-engage choke, full throttle or close to full throttle so choke does not close, crank for 5 seconds. Report your findings back here, someone will make a comment. If you have no success, listen to advice/checks here, but only check/test one thing at a time.

The 31 series engine also have a big problem blowing head gaskets across to the pushrod gallery. They can blow through the middle layers of the gasket, gasket in place. Zooming in on your image, there is a small section that may be damaged. Aftermarket solid copper gaskets are available for these engines. Check this is the correct one if you wish to follow it up and I'm sure there are other suppliers of different gaskets.

2201 .032 Copper Head Gasket for Briggs Model 31 OHV - EC Carburetors

www.eccarburetors.com

I won't go into checking head/cylinder for flatness here. Don't forget to tension head to 220 lb-in in correct sequence . Do not torque each screw in one step as it may result in a warped cylinder head. Step-torque all screws to approximately 1/3 of final torque value, then to 2/3 final torque value, then finish at final torque value.
When 4 bolts are on left side, from top to bottom, 5, 8, 6, 3, then middle two, top is 2, bottom, 1, then two on right, top is 4, bottom is 7.

If you are in any way hesitant or don't have the skills to do any of the above safely, especially with regards to fuel (liquid and vapor), ignition sources from spark plugs or shorted wires, please leave it to the professionals. These are my thoughts only, others on this forum, professional or otherwise may have different views, that's fine, go with them in preference to me. I believe the torque specifications and patterns are correct for your engine, but you need to check that they are. Actually, take all the above with a grain of salt.

 

[PapaDrew88]

What are you torquing the flywheel nut to

What are you torquing the flywheel nut to?

Just tightening it up by hand with my 1/2" drive ratchet

 

[PapaDrew88]

I note some things I would do, but from a safety aspect, you should refrain from the following and allow a professional to do your repairs. From your first post, it appears everything was basically good, except that the mower stopped, get back to original and check one thing at a time.It appears that some basic checks may not have happened before tearing down and changing things. No worries, I would just try to get back to original and check one thing at a time.

As previously noted, there is a possibility that the flywheel has been incorrectly installed or torqued incorrectly and has slipped/sheared. A backfire can shear a key at any time, especially if it wasn't replaced or torqued correctly. Clean/fine sand paper the flywheel and shaft with 1000~2000 wet/dry.
Remove key, install flywheel without key, make sure it is set down evenly and doesn't wobble, do up flywheel nut, torque to spec 100 lb-ft (use a tension wrench), measure the length of the thread protruding past the nut with a vernier, also mark/scribe a line from the nut to the flywheel, undo, remove flywheel, place key in-situ, replace flywheel/key, ensure even and no wobble, tension nut and check with vernier that it is the same, and check scribe mark. Many times a key may hold up the flywheel by a tiny amount, it is the mating surfaces of the taper that do the holding, not the key, the key is only a locating/alignment device, and it's generally made of aluminum so that it shears if the forces on the mating surfaces are too great, and can be easily replaced without damage to shaft or flywheel.

Put the ORIGINAL ignition coil back on and set air gap 10 to 14 thousandths of an inch. (use feeler gauges)

Carefully check all wiring for any rub through that may blow the fuse (entire mower wiring harness)

Turn off any ancillaries on the mower, headlights, blade clutches etc.

Slow charge the battery overnight so it is fully charged before you start any investigations again.

Check oil level, if it is over full, completely drain oil and replace with new oil to correct level. If it is low, either top up, or drain /replace to correct level.

If your model has the fuel tank above the carby and uses gravity flow, remove bowl and turn fuel on and ensure good flow, then carefully use a pencil or other apparatus to lightly lift the float to ensure easy fuel shut off. If fuel is low and uses a fuel pump, run a fuel hose from a small bottle above to do the same test. If fuel shut off is not accomplished with very light pressure on float at approx horizontal position, replace needle.
As you have stated you have a fuel flooding issue, ensure the previous step is carried out thoroughly. Also, if you have a crankcase/differential/electric pressure driven fuel pump, disconnect the fuel supply going to it, and from it and rig up a gravity feed fuel supply to the carby for testing/running until engine running is sorted. This gets rid of fuel pressure and also possible fuel leakage past the diaphragm into the crankcase or intake or where-ever this pump is plumbed to.

Ensure no flammables in work area. Ensure no fuel, liquid or vapor leaks in general area. All testing to be done in a wide open outside area with approiate safety/fire extinguishers etc.. First engine test, no air cleaner, fuel tap off if it has one, gravity fed fuel, remove spark plug, plug spark plug into high tension lead and ground the plug well away from the plug hole, well away from the carby, open throttle wide, but not so that choke flap closes, crank engine and check for spark, crank for 10 SECONDS and check that spark stops when key is turned off and engine is still spinning.
Replace spark plug into plug hole, tension to 180 lb-in.
Plug high tension lead onto spark plug. Turn on fuel, allow 30 seconds, manually engage choke or ensure choke lever has engaged at full throttle, crank engine for 5 seconds, or less if it fires. If it doesn't fire, dis-engage choke, full throttle or close to full throttle so choke does not close, crank for 5 seconds. Report your findings back here, someone will make a comment. If you have no success, listen to advice/checks here, but only check/test one thing at a time.

The 31 series engine also have a big problem blowing head gaskets across to the pushrod gallery. They can blow through the middle layers of the gasket, gasket in place. Zooming in on your image, there is a small section that may be damaged. Aftermarket solid copper gaskets are available for these engines. Check this is the correct one if you wish to follow it up and I'm sure there are other suppliers of different gaskets.

2201 .032 Copper Head Gasket for Briggs Model 31 OHV - EC Carburetors

www.eccarburetors.com

I won't go into checking head/cylinder for flatness here. Don't forget to tension head to 220 lb-in in correct sequence . Do not torque each screw in one step as it may result in a warped cylinder head. Step-torque all screws to approximately 1/3 of final torque value, then to 2/3 final torque value, then finish at final torque value.
When 4 bolts are on left side, from top to bottom, 5, 8, 6, 3, then middle two, top is 2, bottom, 1, then two on right, top is 4, bottom is 7.

If you are in any way hesitant or don't have the skills to do any of the above safely, especially with regards to fuel (liquid and vapor), ignition sources from spark plugs or shorted wires, please leave it to the professionals. These are my thoughts only, others on this forum, professional or otherwise may have different views, that's fine, go with them in preference to me. I believe the torque specifications and patterns are correct for your engine, but you need to check that they are. Actually, take all the above with a grain of salt.

Thank you for this detailed explanation, everyone has been so generous with troubleshooting tips. I've learned so much. The broke mower was given to me so I'm determined to fix it on my own. I will get back to troubleshooting using these tips once the weather clears up a bit.

 

[Scrubcadet10]

31 series has a 100 Ft Lb flywheel nut torque

Give us the complete model number off of the Valve cover and i can make sure the spec is correct.