641 workmaster bogging down

[cb in wisc]

I am trying to do some mowing with a ford 5 foot rotary mower on a 641 workmaster and it is constantly bogging down and losing power.
I am traveling in first gear low range ( sherman transmission) and the grass/weed mix has been previously been mowed, so it is not that tall.
I am also keeping the mower raised a few inches and have the back end of the mower raised higher than the front for easier discharge of the cuttings. Running at the 540 pto speed. On a flat or downhill it keeps running, any incline or a bit of thicker grass and it just bogs right down and doesn't maintain rpm's. Any Ideas on how to correct this condition? Even driving up the driveway, without the mower, in a higher gear, will bog down the engine and I have to shift to a lower gear.

 

[used red MN]

I am trying to do some mowing with a ford 5 foot rotary mower on a 641 workmaster and it is constantly bogging down and losing power.
I am traveling in first gear low range ( sherman transmission) and the grass/weed mix has been previously been mowed, so it is not that tall.
I am also keeping the mower raised a few inches and have the back end of the mower raised higher than the front for easier discharge of the cuttings. Running at the 540 pto speed. On a flat or downhill it keeps running, any incline or a bit of thicker grass and it just bogs right down and doesn't maintain rpm's. Any Ideas on how to correct this condition? Even driving up the driveway, without the mower, in a higher gear, will bog down the engine and I have to shift to a lower gear.

Have you tested the flow of gas out of the drain plug in the carb? Need a pint in 2 minutes. To make the test legitimate pull the plug and wait 5 seconds, this allows the reserve in the carb bowl to drain down. After the 5 seconds catch the gas and start a 2 min. timer.

 

[BradCNY]

I am trying to do some mowing with a ford 5 foot rotary mower on a 641 workmaster and it is constantly bogging down and losing power.
I am traveling in first gear low range ( sherman transmission) and the grass/weed mix has been previously been mowed, so it is not that tall.
I am also keeping the mower raised a few inches and have the back end of the mower raised higher than the front for easier discharge of the cuttings. Running at the 540 pto speed. On a flat or downhill it keeps running, any incline or a bit of thicker grass and it just bogs right down and doesn't maintain rpm's. Any Ideas on how to correct this condition? Even driving up the driveway, without the mower, in a higher gear, will bog down the engine and I have to shift to a lower gear.

Doesn't the Sherman in low range slow down the pto speed, (I know it does in my 8N). Need to keep mower speed up for a better cut and not just thrashing the grass.

 

[Sean in PA]

Doesn't the Sherman in low range slow down the pto speed, (I know it does in my 8N). Need to keep mower speed up for a better cut and not just thrashing the grass.

Yes, the PTO is driven by the transmission counter shaft, which is driven off of the transmission input shaft. The Sherman slows down the input shaft of the transmission when it is in the step-down gear (low range), so you need to increase the engine rpms accordingly. You basically need to get to the same ground speed that the trans without the Sherman would run at when at normal PTO speed.

 

[Eman85]

Most tractors that age are tired, is yours? A basic evaluation of the condition with a compression test is a good starting point. From there a if it's got good compression a valve adjustment, fuel flow test and evaluation of ignition system condition would be next.