Hi,
I have a 19hp intek motor in my craftsmanT1600 mower, I had a failure of the magnets on the flywheel so I bought a new one on eBay, I also installed a new coil and stator and spark plug, I have a good spark at the spark plug but I cannot get the engine to pop or fire even with starting fluid, I even checked the fuse under the battery which was good, it cranks and cranks with no fire at all, any ideas as to why it won’t start?

Thanks,
Dave

Remove the air filter, squirt some carb cleaner or brake cleaner down the throat 
and try to start it.
 
If it starts momentarily, you have a fueling issue and we'll go from there..
 
Advise..
 
 
.

Ya, I tried that with no luck, even bought a new carb and installed it, nothing so I reinstalled the old one back on, shutoff valve is new and I can feel it click when ignition is on, I’m stumped

Please post EVERYTHING you did...  
 
Also, did you check to see the flywheel key way is in the same position between both
flywheels?
 
Did you check compression and / or valves going up and down under the valve cover?
 
.

I replaced the head gasket 2 months ago, been running great, I lent the mower to my son in law to mow his 5 acres and it started popping, when I got it home I saw magnet fragments on the motor so I knew I had magnet failure, I then ordered a new flywheel, stator, carb, I believe the key is in the right place, it’s the same part numbered flywheel as my old one but came off a 17hp motor I believe, I reinstalled everything and have spark but no fire

Popping is often due to timing being off. 
 
I would access the flywheel and MAKE SURE, the magnets are in the same position to the keyway
between both parts...  
 
Did you torque the flywheel to 100 ft lbs?
 
On the coil, is the ground wire "tab" facing the block (not visible)?
 
I gather the engine has not run since the initial "loan out"?
 
.

Just checked valves and they are going up and down as they should

Motor ran briefly when I picked it up, ran better at lower idle, then when I got home it wouldn’t fire, this is a pic of the old flywheel with the failed magnets

What valve clearances do you have them set at?
 
Also, when closed, are they at about the same height?
 
.
 
.

Yes, tab is facing block, did not torque the flywheel but installed with a electric impact drill, carefull not to overtighten