I haven't seen too many steel keys "shear" off. I've seen them tweaked from hitting a hard object. Since you're heading there, observe the key and flywheel area to make sure it's properly aligned and the wheel is not cracked from striking something. If all is good, I'd bet the "starting" side circuit of the CDI has taken a dump. Try replacing it. Check the ports to make sure they're not coked up with carbon also.

ports are clear it prob has less than five min run time you should see the under neath of this mower. It hasn't hit any thing both ends of the blade are perfect. Even though it has spark you think the cdi still might be bad. The spark looks strong.

Do not ever use 'starting fluid' in a 2-cycle! It washes the oil off the cylinder walls and the rings can seize to the iron cylinder liner. Put only mixed fuel in it through the air cleaner box. You can put some mix in a little squirt bottle, take out the air filter and shoot it into the throttle body. Visually check to see if both blades of the reed valve are still covering the intake port.

yeah both shiny blades are there. i only did start fluid one time its ok. I think something is wrong timing wise. Not really sure. I poured 2 cycle oil down spark plug hole before i sprayed the starting fluid in there.

Its either a carbuerator thing or flywheel key. I'd at least check the key to rule it out.

See if the flywheel magnets are functioning. They both should hold a wrench tight.

The carb may have a clogged jet. You say it pops a little with starter fluid. It needs gas so recheck all the carb functions.

The spark plug will be wet after several pulls with no start when the choke is on if its sucking gas.

Neal

Forget the carb. You bypassed the carb by squirting gas in it. Ignition seems fine if you are seeing a good spark. My guess is it popped the crank seal out under the flywheel. Check the lower one also. I had one with your exact symptoms the other day. Crank seal was popped out....

rdaystorm. I had a cracked primer bulb. Put new one on and pulled it over after i primed like four times. The mower will run for like four or five seconds very low rpm seems. So it seems to be getting gas. Whats the easiest way to check the seals if it stills sounds like it to you?

"Whats the easiest way to check the seals"

Check for wet, oily, crude just outside the top and especially the bottom seal on the crankshaft and surrounding area.

As for crankshaft key, very few (I have never seen one in 40 years) LB crankshaft keys are sheared or even deformed to the place they would cause your symptoms with a CDI Unit. Cracked Flywheel thru the keyway, maybe.

The opposite of above, the Start Phase of the CDI Unit may be good, that will normally let it run continuously but only at about 800 rpm if the RUN Phase of the CDI is bad.

Walt Conner

Walt I cant figure this mower out. I checked compression it has
100 psi when i pull it over. If i don't prime it mower won't run at all. I checked the spark and when i pull it over it looks like my dura force spark. so i assume thats not the problem. I dont seem to think that it is fuel because i can prime it and fuel comes out of the bowl part.

This engine has to have good seals on the crank to run - so it will draw in fuel/air when the piston goes up, then compress it in the crankcase when the piston is driven down. You will see lots of oil and black goop around the seal if they leak too much (except your mower has one hour on it so there can't be any black goop there). They have to leak a little to let compression blow fuel/oil through the bearing to clean and lube it and lube the seal, but it shouldn't be a lot. The seal may have just popped out, too, which happens sometimes. By the way, have you pulled the muffler and taken a look at the exhaust ports? I know, it should be fine since it's basically new, but you never know.

Could be something as simple as the float needle stuck closed from sitting so long. That wouldn't answer why it stopped when new and wouldn't restart.

Did you look to see if the bottom seal had come out?

Walt Conner

Well I see now that you cleaned the carb. The throttle butterfly is working OK? Did you look at the reed valves when the carb was off?

Walt Conner

Ill take it to my shop today and check out that bottom seal. The throttle butterfly moves. The white plastic peace goes back and forth and has metal spring on it? Ok now for the reed valves when i took the carb of the shiny metal when i look down in is not tight up against i can see space inbetween. Not really sure how to tell how the reed valves work?

It's just a piece of spring steel over a hole, a 'flap' valve. Since it's on the inside of the hole, it will let air in but is forced shut when the air tries to get out. It has two 'tongues' over the two intake slots and normally has a clearance. If one of the 'tongues' is broken off the engine will not run. See my post above about 'compression in the crankcase'.

The reeds look good. Do i have to take alot off to see the seals took muffler off looked up in and only see metal. So assuming i need to take engine off deck to check them? Bare with me im a mower engine tinker first timer lol.