Mower suddenly can't stay running.(Kohler XT-675)

[juntjoo]

The two pics are the new one I just popped in and the other outside is the old one to show I'm using the same carb, although not exactly like the original which has a thermostat connection on the exhaust, I guess to the choke(?) so apparently it works as it has with the choke open and not controlled by anything.

Anyway, with new plug and new carb replaced I've still got this start but stalls shortly after. By default the throttle and choke rest open.

The old plug looked wet though idk how wet it should be. I presume the new plug will look the same. Starting now with new carb and spark it's barely running before it stalls. What should I check/do now?

 

[juntjoo]

Here's a video for a audio/visual test

 

[sgkent]

in order to run an engine needs compression, a reasonable air to good fuel ratio, and spark. Whenever an engine fails to run the first step is to determine which is missing of the three. If you just guess then you will be there for a long time. I would pull the air cleaner off and see if the choke is opening when it starts. If not then use a screwdriver to hold it open and try again. If it then runs something is wrong with the choke. If the air cleaner is dirty or the fuel old, that will make it hard for a mower to run.

 

[VegetiveSteam]

Get some way to keep the choke wide open and see how it runs. Without a connection to the choke thermostat there is nothing keeping the choke open. With the choke being loose, once the engine starts the drawn in air simply closes it.

The new and the old carb look the same. What happened to the link that connected the choke on the original carb to the choke thermostat on the muffler?

 

[juntjoo]

Thanks for the tips. I will look more carefully into the choke. Til now I've been running it with nothing controlling the choke so I'm assuming it's been just hanging open. Maybe it's been closing unnecessarily? I did order a coil so just in case otherwise I'll keep it on hand

 

[slomo]

That plug is waay wet. As in carb needle sticking open wet. Pull the oil dipstick and smell for fuel in the oil.

How much was the Amazon carb?

 

[juntjoo]

That plug is waay wet. As in carb needle sticking open wet. Pull the oil dipstick and smell for fuel in the oil.

How much was the Amazon carb?

The wet plug is from old carb actually

Okay. So new plug, got spark, well, a little red light from my spark tester. Don't know if that's conclusive. Should it be so bright? New coil, current plug not wet, new fuel filter...

It WAS at least starting, now nothing. What's next?

Should the coil touch the flywheel? There's room in the bolt holes to adjust

 

[bertsmobile1]

Coil should be 0.010" off the MAGNETS .

 

[juntjoo]

Coil should be 0.010" off the MAGNETS .

Got that. No difference. This one's puzzling.

How do you reliably check for proper fuel to cylinder? There's only vacuum force to pull it right? Do you just check the spark plug or should I stick a camera up to the open air box? I sure smell fuel when I attempt to start it. I've assumed that was enough confirmation

I can check for compression too but would I notice it turning over easier if that were the case?

What about timing?

Could the exhaust be so gunked up to interfere with proper air flow?

 

[juntjoo]

So I should mention it is hard to pull the rope/turn the engine over. Maybe something deep going on like bent shaft or something? I have to start pulling slow to make sure it catches otherwise it gets stuck. Is this something common related to a particular issue?