Problem with Fan Limit Switch on Keystoker

This is the first time I have posted a question. I have a Keystoker 90000 BTU stove and it is thermostatically controlled. The fan limit pointers are at the standard spots--- 200, 150, 120--- but when the fan turns on, it runs for only 20-40 seconds and then turns off. The needle goes down only slightly below the 150 mark and then the fun turns off. I am hoping that there might be a fix for this and that I do not have to pay for a new fan limit switch.
Thanks for your help.

mine is at 100, 140 and 200, normally runs for a little while and then shuts off. sometimes only a few minutes or longer. or separate the values for 120 and 150 more. ?

maybe something wrong with yours or spring or somthing is broke in it? or it's catching on something.

Never twist the movable part...that will screw it up!

Snap-switches can work also...maybe not cost as much as a new fan/limit???

snap+switch+thermostat

My blower on the Clayton has been kicking on and of about every 3 minutes. I ordered an ICM326H so I can run the blower at a slower speed. It’s cooling the fan limit too quickly.

also depends on how warm the stove is running, if not real warm, it will kick on and off more often. When mine is cranking, the fan will run much longer since it won't cool down as much.

Running for less than a minute seems odd. I have a Keystoker koker. Mine is set at 140 and 110 and with the thermostat, keeps my first floor within a degree of 71 all winter. I have a digital thermometer stuck in the duct near the stoker supply in the basement. The limit switch is pretty accurate according to that. I did run into an issue last year with my blower motor acting funky. When it would shut off I would hear a hum. Nothing I had heard before. I moved one of the filters on the blower and the drum was still rotating at a very low speed. Thought the motor or cap was going bad. After some investigation, I realized the white manual override button on the limit switch was pushed in slightly. Once I pulled it out all the way, problem solved. I must have bump it when filling the hopper. I’d check that as well as spread the pointers a bit as was suggested. Mcgeiver is right, hold the center of the rotating disk when adjusting the pointers. If all that fails time for a new switch. Amazon has them for less than $100. Let us know how you make out.

Thanks everyone for the suggestions. My understanding-- maybe wrong--- is that the fan blower is controlled by the internal air temperature sensor, not the thermostat. With the cover off the fan limit switch, I can watch the temperature needle move, and it moves only a few degrees before the fan motor switches off. If I push the manual override button in, and then the needle moves down fully, so the needle isn't stuck, it will move. I am not sure what adjusting the pointers will do, but I can try it (carefully, thanks for the warning). I just looked at Amazon and I see a Keystoker fan limit switch for $140 and other brands (Honeywell, etc) for less. Do you know which ones are interchangeable?
Again, thanks much for the help!

adjusting it will change the on/off temperatures. You might able to get it to run longer depending your settings. they might be too close and it cools down too fast. Raise the ON up maybe 10 degs and lower the OFF down 10 degs (approx) and then adjust from there if it runs too long and blows cooler air, etc....might be just dirty and need to be moved back and forth.
Yes, it runs on the stove temperature, independent of the thermostat. the fan switch only controls the fan.
not sure what's interchangable. Def. not cheap. but a thermoswitch or digital temp control might work also to control fan.
good luck with it, i've had my Keystoker over 15 years with no issues.

Mine has a Honeywell. Original as far as I know. You can also call keystoker. They are very helpful.

Thanks everybody for the help and suggestions. I called Keystoker and as you said they are very nice. They talked me through doing a few things and concluded that the switch is bad. It is a Honeywell and apparently there have been quality problems since Honeywell switched production from US to elsewhere. I called my vendor and today I have a switch that works. Good, because it's cold outside. Thanks again--- this is a great message board.

Glad to hear it is all fixed!