Suburban furnace burners not staying on?

[nwirt74@gmail.com]

Our 2013 36RE , suburban furnace SF-42, isn’t working properly? Up until yesterday was working properly? It gets a call from the t-stat for heat, I go outside and notice the furnace blower engage, hear the burners come on, feel heat from the exhaust, and after a very short time the burners go off without reaching the t-stat set point? Flame sensor? High limit? TY in advance for the help?

[XCMARK]

any chance mud wasp built a nest in the heat exchanger? IF it runs for 10 seconds then goes out Then I would look a the flame senescing thermo coupler.
It hard to say not knowing how long it really stays running and if it sounds different then it used to. Does it relight right after it goes off or does it have to be reset ?