Craftsman LM only starts after sitting in sunshine

[Vancouverite]

I have a Craftsman 675 Series B&S push lawnmower 944.367450 model approx 5 yrs old. It seems my LM will not start unless it sitting in the sun for at least 15 minutes. It could be clouldy at 70F and it still won't turn over. After 15 minutes in the sun...boom first pull. I've tried changing the spark plug, air filter, engine oil, emptied old put in new fuel and dismantled carburator 3 times cleaning it with carb cleaner including checking/cleaning jets. Still no luck. Anyone have any suggestions?

 

[midnite rider]

Check that the engine safety shut off switch/cable is not binding or sticking.

 

[Vancouverite]

Inspected Operator Presence Control Bar cable to switch. Seems to be ok.

Forgot to mention. Lawn mower has an automatic choke.

 

[possum]

Pull the air cleaner when it is cold and check to see if the choke is closing. The thermostat device behind the muffler can stop working as well as dirt and trash buildup in the linkage under the flashy engine cover. My neighbor has two snappers that mow like mad but to start them takes a bunch of incredible hard wild pulls from him and his sons to get them going.

 

[Vancouverite]

Wondering if it needs a carb replacement. Either that, or just cut the grass only sunny days. Seems bizarre.

 

[EngineMan]

Have you check out the choke to see if that working the way it should be..? when engine's are warm or hot they don't normally require choke. maybe that's why it wants to sit in the sun...( would love to be able to do that one day) :laughing: that is where I would look.

 

[pugaltitude]

There is a briggs bulletin on cold start problems on the readystart.
You said you replaced spark plug. What gap? Should be .030"
Check thermostat for binding.
Check and make sure choke is coming on.
If not then you have to check and adjust thermostat to make sure it is adjusted correctly between the notches on the choke lever.
If all these fail then it could be a new carb required.
Have you reconnected the small choke lever spring which isnt allowing choke to go on?

 

[Vancouverite]

Thanks Engineman and pugaltitude. I will do inspection on the choke. Yes the plug gap is at .030"

 

[Vancouverite]

I exposed the fly wheel removing cover. Noticed thermostat was properly in place in between notches as mentioned. There didn't seem to be any issues moving choke linkage. Choke is fully opening and closing. I did not mention earlier but yes, small choke lever spring is inserted correctly.

 

[EngineMan]

What type of kill switch does it have, is it a microswitch, had one of them play up on a mower would start then it wouldn't gave it some WD then alright for a few days, in the end a new one was fitted.
before you take it out into the sun, and you have pulled it many time's without it starting, is the plug wet.