How long to choke?

[EternalArianne]

Sometimes after cranking, but not all, I have to leave the choke knob pulled out for a solid minute before pushing it in, or else the engine will sputter and die. Other times I can push the choke back in after only 10-15 seconds of cranking.

What is the normal amount of time to leave the choke knob pulled after cranking? Is there a reason sometimes I have to leave it choked for longer and other times not?

I have the Command 15 Single Cylinder if that makes a difference.

[Billy-O]

Every engine is different. Some need a little choke till you get some heat into it. The colder the weather, the more choking is needed. It also depends how you have the carb set for engine fully warmed at idle and WOT.

In my case both 124 and 125 starts 1-1/2 to 4 turns and I open the choke fully once it fires and throttle is lowered to just above idle till ready to rip. Even in the winter.

[EternalArianne]

I’ve noticed that on the times I have to leave the choke open longer, the idle “surges” up and down after I push the choke knob in. I can correct it by going WOT for a bit then lowering it down. It’s like the air/fuel mixture isn’t quite right, but it only happens occasionally.

The engine always seems to “settle down” after running for a bit regardless. Temperature has been about the same since I got the tractor a while back, 80-90+ Fahrenheit.

[ol'George]

One thing to always remember:
Never EVER,EVER run any engine fast when it is first started.
Oil needs to be circulating freely or y'all don gonna cause premature wear.
---Just the nature of things mechanical.
It matters not, if the engine is pressure lubricated or splash system.
An engine when first started, as stated, needs a richer mixture till the combustion chamber warms, then the mixture can be leaned by opening the choke appropriately, then fully opening, it usually only takes a minute or two.

Newer fool injection engines do this without having a choke as they have a fuel enrichment program in the engine management module.

An older engine with adjustable jetting, if set lean, will need more choke than one set richer.
Atmospheric conditions like air temp, humidity and barometric pressure also cause variations in the amount of choke needed in carbureted engines.
One just learns to "listen" to the engine, applying the necessary choke as needed, during that first couple of minutes of operation.
it ain't rocket science.
If a carbureted engine is warm to the touch, it needs no choking.

[EternalArianne]

Thanks George, I’ll keep that in mind to not WOT until warmed up. I was only doing that to try to correct the idle surging. Normally I follow the cranking instructions on the sticker by the right foot rest.