LTX 1045 Cranks but no start

[tenisprola]

Frustrated beyond words. 2006 model with lots of repairs along the way .
Started it after winter storage, and it caught fire (after 1 hr use ) because of a mouse nest.

Poured cold water on it in a panic , but luckily don't think i cracked the block.

It did start immediately . Cleaned it up ( temp repair on spark plug boot ) also fixed leaky cork valve cover gasket( 10 years of oil leak ) , and replaced melted plastic fan cover.

Was working fine for 2 mows then started idling slow and eventually puttered out . Starter would not turn it , but could be turned ( lots of resistence ) by hand .
Thought it was starter , so disasembled & discovered 3 of 4 magnets unglued. used JB weld to glue magnets on and assembled . Starter still unable to turn flywheel more than 1/4 rotation .

Opened up valve cover to discover rocker arm loose,(set screw almost off ). Tightened back up and the flywheel was back to normal and would rotate freely by the starter.
Mower still not firering up . Was using 1 year old fuel , so took fuel tank off and drained / replaced with fresh fuel.

-fuel pump( replaced with CC original part): has flow into carb intake hose upon engine cranking .
-fuel filter ( not clogged but replaced )
-ignition module (lights up tester with flywheel rotation ) but replaced with CC original part
-carburator ( replaced with non CC original part ) , solenoid seems to engage ( clicks with key turn)
-took flywheel off ( cleaned ) and checked for sheared key /woodruff key looked intact
- adjusted valve clearence to spec per manual ( at TDC of compression )
-changed spark plug and gapped
- made sure throttle and choke linkeages work properly
-it has oil to proper level
-by passed seat safety switch
-by passed brake pedal switch
-air filter and housing off
-bought new CC original starter but not intalled ( original starter working )
-made sure not to reverse polarity of magnets on glued starter by checking rotation of flywheel against that of new starter , and has same clockwise direction
-sprayed stater fluid into intake and cranked but no ignition

please help .....What should i check or recheck next ?

 

[bertsmobile1]

In short,
Everything that you have done
The problem with throwing parts at the problem without diagnosing the problem first is now you still have the original problem + potentially a pile more from the work you have done .
So toss a small amount of fuel down the plug hole
The engine should fire once or twice if the valves are closed & the timing is correct .

If that works squirt some starting fluid ( carb cleaner is better than starting fluid ) down the carb throat .
The engine should run for 1/2 a second or so if the valves are working properly

If both of these tests work then you are left with the carb

Come back with the results

 

[tenisprola]

Thanks for your comments. You're so right & Wish i had the know how to diagnose the original problem .
Took out the spark plug, Put a tablespoon of fuel in the hole reinstalled the plug/wire , cranked and it threw all the fuel out of the muffler. Cranks like a mf though but no ignition ....

 

[bertsmobile1]

Take the plug out crank the engine a few seconds then try with a fresh plug & no added fuel
If it goes bang then we are good to go
If not
With a fresh spark plug, try that again with 1/2 TEASPOON , no more of fuel down the plug hole
Too much fuel just floods the engine so the plug gets wet and inside the cylinder the spark will just run down the sides so no bang , in fact a 1/4 teaspoon would be more than enough .
If nothing else we have confirmed the exhaust valve is working so we are making progress

 

[StarTech]

As Bert too fuel can foul the spark plug tip.

Remove the spark and confirm spark by grounding to the engine crankcase while cranking. Use glove to insulate yourself or a nasty shock is possible.

Now with engine over heating due mouse bed you could have a damage cylinder head. Valve seat may have worked loose which would cause the excessive rocker clearance.

 

[evh]

I doubt this is it, but I didn't read where you replaced the spark plug. I had a plug on a tractor years ago that the spark was more like a flash (only way to describe it). Mower would not start or pop. I replaced with a new plug, started right up. Again, I doubt this is it, but worth a try. Sounds like maybe a timing (check the key) or valve issue.

 

[tenisprola]

Take the plug out crank the engine a few seconds then try with a fresh plug & no added fuel
If it goes bang then we are good to go
If not
With a fresh spark plug, try that again with 1/2 TEASPOON , no more of fuel down the plug hole
Too much fuel just floods the engine so the plug gets wet and inside the cylinder the spark will just run down the sides so no bang , in fact a 1/4 teaspoon would be more than enough .
If nothing else we have confirmed the exhaust valve is working so we are making progress

 

[tenisprola]

I’ve poured 1/4 teaspoon with syringe down the spark plug hole , reinstalled. No ingition
Tried with carb cleaner too and nu success . .
. Grounded the spark plug while cranking and yes it gets spark and even jumps on the engine block .
any other ideas ?

 

[tenisprola]

As Bert too fuel can foul the spark plug tip.

Remove the spark and confirm spark by grounding to the engine crankcase while cranking. Use glove to insulate yourself or a nasty shock is possible.

Now with engine over heating due mouse bed you could have a damage cylinder head. Valve seat may have worked loose which would cause the excessive rocker clearance.

thanks for the suggestion . i have several new plugs , and the all spark well when grounded . The spark jumps on the engine block too

 

[bertsmobile1]

Take the nut / bolt that holds the flywheel on and check the timing key .
The slot in the flywheel & the slot in the crankshaft should come together to make a perfect square .

Remove the rocker cover and check the pushrods are in place and that the valves move in & out.
The cam grinds are the same for inlet & exhaust and the valves are the same length so they should move the same

Finally pop a pencil down the plug hole & check that the piston is going up & down

One of these 3 is not happening