Portable buddy troubleshoot. Fixed!!!

[Fish Butcher]

Heater fires up good, runs a minute or two, then kicks out. Same result, time after time. Last year did the same thing but got worse as the season went on. I suspect the tip over switch. A link to a diagram and disassembly instructions would be appreciated. Model MH9BX. Of course my diagnosis is open to discussion.

[DR.SPECKLER]

When my tipover switch sticks the pilot light lights but as soon as i let off the button it goes out.give it a smack on the side and try it but I suspect the thermocouple going bad.

[Fish Butcher]

I let up the button and it runs great but only for a minute or two. Will search thermocoupler again.

[3300]

https://www.mrheater.com/10-000-btu-vent-free-radiant-natural-gas-heater.html?serial=9#schematics

http://www.manualsdir.com/manuals/121231/mr-heater-mh9bx.html?page=6

https://www.manualslib.com/manual/630862/Mr-Heater-Mh9bx.html

https://www.ereplacementparts.com/heater-mh9b-heater-parts-c-197733_197735_202230.html

[Fish Butcher]

First off. Thanks 3300 for the links. Problem was the tip over switch had one ear broken causing switch to sit at an angle being fastened loosely by one ear only. Slightest bump or heater at small angle and game over. “Macguivered” switch to base and now I’m back in business.

[3300]

this information all adds up for the next time a mr heater gives issues. do the ears seem fragile?

i've only had one apart to modify the pilot to thermocouple distance to help it stay lit. for myself the flame at the pilot on cold starts wasn't strong enough to keep the thermocouple hot enough and took much longer to have to hold the start button down to get it lit. this was done to the portable heater only. my big buddy and little buddy are stock still.
*this does defeat the so called low o2 cut off detector as this distance is made this way so if the flame becomes weak from lack of o2 it shuts of the gas valve by tripping the thermocouple.

bart made a flame guard to wind proof the pilot.

thanks for the update and glad you figured it out!

[Fish Butcher]

I would not say the ears are fragile, just plastic. And at cold cold temps we all know how fragile(brittle)plastic can be. Please note this was on an old, but newer, red model. On my older green, portable buddy, heater I also moved the thermocouple up a bit and installed a flame guard. The newer model has a deeper pan and a flame guard has not been necessary for me. Flipover fishing only with both units.