Engine turns over, but will not crank.

Here is the background information:
John Deere Z425 (2011) with Briggs and Stratton 23 hp (model 44L7770144G1)

When I went to start the engine, no problem. When placing choke lever to run it shuts off and will not crank again. The engine turns over but that is it. I cut grass last week without any problems. Things that have been checked this time or replaced last time: Spark plugs are clean, replaced last year, tested with a plug tester. Fuel pump replaced last year and tested this time for fuel discharge. Replaced fuel filter last year, verified it is clean. I don't suspect any of the safety interlocks because the ones I have tested won't allow the engine to even turn over. Checked the oil in the operating band. I took it to a shade tree mechanic last year and of course it started right up when I got there. Any ideas or suggestions are greatly appreciated.

Thanks

Robert

OK Robert, we need to get things strait.
You have the mower in front of you.
All we have is your words.
Crank = to rotate using starter motor or pull cord
Fire = goes bang but not necessarily
Start = fires for a short period of time & rotates under its own power
Run= work..

We also need to know if it has a choke and a throttle ( 2 controls )
or
a combined choke & throttle ( 1 lever )

My JD Z445 has been terrible to start for years. Sent it to the JD dealer in the fall and $900 later they dropped it off. Guess what? First time I tried to start the mower it wouldn't start. Not happy. No answers for you. I also did everything you did. I'll watch this thread to see if someone has any ideas.

bertsmobile1 said:

OK Robert, we need to get things strait.
You have the mower in front of you.
All we have is your words.
Crank = to rotate using starter motor or pull cord
Fire = goes bang but not necessarily
Start = fires for a short period of time & rotates under its own power
Run= work..

We also need to know if it has a choke and a throttle ( 2 controls )
or
a combined choke & throttle ( 1 lever )

Click to expand...

It did start and run for a few seconds. Now it will only crank. I have good fire according to my spark plug tester. It has a combination choke and throttle lever. This has happened a couple of times over the last year. It has eventually "Fixed" itself in the past, nothing I did seem to work.

Thanks

Good,
now get some starter fluid in a spray can and give the mower a short shot through the carb.
If the mower starts and you can keep it running for say a minute by giving it some more short shots, you have a fuel delivery problem.
If no go you have an electrical / timing / valve problem.

bertsmobile1 said:

Good,
now get some starter fluid in a spray can and give the mower a short shot through the carb.
If the mower starts and you can keep it running for say a minute by giving it some more short shots, you have a fuel delivery problem.
If no go you have an electrical / timing / valve problem.

Click to expand...

OK, I got the starter fluid and gave it a shot in the carb. I was able to keep it running like you said. I took the fuel line off of the carb inlet. I have fuel out of the line when cranking the engine. When I replace the fuel line it still will not start without the starter fluid.

UPDATE:
I got it running with the use of a HAMMER! Found a video with an old timer, he said to tap gently on the carb while cranking it. (Small hammer) Some sort of valve or float sticks due to gunk, most likely due to the couple of times that I was too sorry to find non-ethanol fuel. That won't happen again. So now the question is, will a fuel additive be enough to clean out the carb? And thanks for your help in steering me in the right direction, the starter fluid idea would have saved me alot of time the last time I chased this gremlin.

Some people have luck with stuff like seafoam or injector cleaners, or Gunk Away or any of those fuel addatives.

Usually on a mower they do not get used enough for the stuff to work.
You would be best served by removing the carb and cleaning it out or even replacing it all together.

Briggs and stratton fuel stabilizer is the best ive used, also, it really sounds like the fuel solenoid is bad, bottom of the carb, wires going to it. They snap shut when the ignition is switched off but they get gunked up sometimes and wont open good, or occasionally get hot and shut in the middle of mowing. U can remove it and turn the key switch to run and off back and forth with the brake set and watch to see it operate properly. If its slow to open or doesnt at all, and is a nasty brown varnishy color u may have found they problem. Hope this helps.