425 and climbing steep hills

[Eaglepb]

I have been reading past post and see some issue with mowing UPHILL and the PT losing power. Is this a major problem. What is the slope a PT425 mowing should be able to do ? What about 60% such as the Hunt vee 6x6? tks.. [img]/forums/images/graemlins/wink.gif[/img]

[SnowRidge]

I believe the Kohler engine is rated at 25 degrees. I don't know what the Robin engine that will go in the new PT-425 can handle, but I suspect it is similar.

Mowing at 60 degrees sounds suicidal.

The PT doesn't actually lose power mowing uphill, but there may not be enough available to both mow and retain top speed, since tramming uphill requires more power than driving on level ground. It all depends on how steep the slope is and how much power the mower requires for the grass conditions at the time. The rule of thumb is: full power to the implement; what's left over goes to propulsion.

Because of this, the operator sometimes has to back off the right pedal enough that the blade speed doesn't drop off when mowing uphill. This is the equivalent of downshifting a manual transmission. This process is not limited to Power Tracs. I have a lawn tractor that acts exactly the same way. My CUT does the same thing when I'm cutting with the 6 foot rotary.

The only time this is an issue is for commercial cutters for whom time is money. One such person that hangs out on this board solved the 'problem' by towing two self-powered mowers with his PT-425.

SnowRidge

[Eaglepb]

tks [img]/forums/images/graemlins/laugh.gif[/img]..I did not mean 60 degree grade. I think the 60 precent slope equals 27 degree grade. What I understand then is that you slow down the tractor. I saw where a 422 had to turn off his mower to have power to go up a hill. That is what started me wondering..tks [img]/forums/images/graemlins/smile.gif[/img]

[SnowRidge]

Sorry, I misread your post. You had 60 percent, not 60 degrees. [img]/forums/images/graemlins/blush.gif[/img]

If my math is correct, the Kohler engined PT-425 is rated at 56 percent.

SnowRidge

[SnowRidge]

</font><font color="blue" class="small">( I saw where a 422 had to turn off his mower to have power to go up a hill. )</font>

Really? Our property has varying slopes that we mow with the PT-425. The steepest is probably close to 25 degrees. We slow a little there, Elsewhere, we only have to slow down if the grass (weeds really) is really tall or wet--providing the ground is smooth enough for us to go flat out.

We are mowing Xmas tree plantations which constrain us to the 48" mower. We cut high, and the grass gets way longer than lawn length between mowings.

SnowRidge

[toolz_not_toyz]

If the Kohler engine that they put in the 425 is fully pressurized, why exactly does it have this 25 degree limitation?

[SnowRidge]

</font><font color="blue" class="small">( the Kohler engine that they put in the 425 is fully pressurized, why exactly does it have this 25 degree limitation? )</font>

The oil slopes in the sump and falls below the pickup tube, I imagine. I think this would be true to some degree with any engine, except those designed to be run in any position, such as those used in aerobatic aircraft. That kind of plumbing would tend to be expensive.

SnowRidge

[MossRoad]

Let's ask Charlie...


Charlie,
What would it take to get the small gas engines rated for aerobatics? Maybe Hans would like this feature [img]/forums/images/graemlins/tongue.gif[/img]

[JerryG]

A deeper sump and/or sump baffling. Is a deeper sump available for any of these small engines?

[Charlie_Iliff]

<font color="red"> Charlie,
What would it take to get the small gas engines rated for aerobatics? Maybe Hans would like this feature
</font>

Every frivoulous question deserves a serious answer. [img]/forums/images/graemlins/crazy.gif[/img]
Most aerobatics are flown with posisive g loads and unmodified engines. The time spent with no oil at the pickup is small and no damage results. True completely dry sump systems with inverted pickups aren't easy to do. For the small engines, for those spending time at more than 25 degrees, why not plumb in a turbocharger pressure oiler on a timer to hit it every 30 seconds or so. [img]/forums/images/graemlins/grin.gif[/img] [img]/forums/images/graemlins/grin.gif[/img]