1872 Loses Power and dies when hot

[Aarono]

I just replaced spark plugs, oil/filter, air filter/element, and cleaned the carb on a Cub Cadet 1872 I "inherited" last year. My cub finally starts up without any starting fluid and runs smooth, but now it starts to lose power and quit after about 15 minutes of use. The motor starts revving down like a wave, and then eventually quits.

Anyone else get this?

My next step is going to be to drain and clean the fuel tank, but I don't have a lot of experience with small engines, etc. I don't see a fuel filter anywhere, so I'm assuming if there is one, it's inside the tank.

[West Valley G]

I would do exactly what you are planning. Pull the fuel tank and make
sure everything is spotless from the tank all the way to the carb.
I would be surprised if there is not a fuel filter in the line somewhere.
There won't be one in the tank.
Next time you run it if it dies. Pull the line coming out of your fuel pump
and see if there is actually fuel being pumped. Pump could be the issue.

Did the problem with it quitting on you start after you rebuilt the carb? Or
was it doing that all along and that is what you were trying fix with the
carb work?

Ken

[Aarono]

I'm pretty sure this model doesn't have a fuel pump.

I don't see a fuel filter anywhere along the fuel line, so that's weird. Maybe someone in the past got rid of it.

It never lost power before, even after running for an hour +, but it did seem to run awful hot.

The main problem before was that it didn't start easily, even after a new starter, but that seems to be resolved now.

I didn't really do much with the carb, just sprayed cleaner in it to perhaps dislodge some gunk. I bought a kit with new seals, etc., but I was a little intimidated about trying to take out the carb and get it back in and functioning without any experience.

[Oak]

This machine should have a fuel pump and a filter. The fuel pump is not needed if the fuel level in the tank is above the carb. Without a filter it will probably clog a jet pretty quick. Pull the carb and clean it, replace the fuel lines, pull the tank and clean it also. Then install new 1/4” lines with an inline fuel filter.
See if the pump was bypassed or being used. It is over by the engine ser#/mod# tag.
You may be having an issue with a mag failing so do the fuel repairs first since they are pretty easy.

[finsruskw]

It does indeed have a fuel pump
And a shut off valve w/screen IN the tank. (illustration #3) in the 2nd pic.
May I suggest you download a copy of the FSM and owners manual for this machine.
It will save you a bunch of questions and headaches.

[Steve N Mi]

Originally Posted by Aarono

it starts to lose power and quit after about 15 minutes of use. The motor starts revving down like a wave, and then eventually quits.

Anyone else get this?

My next step is going to be to drain and clean the fuel tank, but I don't have a lot of experience with small engines, etc. I don't see a fuel filter anywhere, so I'm assuming if there is one, it's inside the tank.

Yes I have had this problem and after doing some of the above I noticed that my gas gage wasn't properly vented. I haven't fixed the problem yet (a couple of vent holes) but I run with the gas cap/gage loose and all is well.

[1711Cub]

Make sure the screen in the bottom of the tank is clean, make sure the valve is opened all the way. The fuel caps on these do fail, so try running it temporarily without or loose to see if it still acts up.

[goonpeden]

As for the motor running hot I would check the screen on the blower housing to make sure it is not covered with debris causing it not to get sufficient air flow to cool motor.