Proposal for 422 vs 425 shootout

   / Proposal for 422 vs 425 shootout #1  

scarg

Bronze Member
Joined
Apr 11, 2004
Messages
99
Location
Upstate NY
Tractor
PT 422 Mod to kawi 29HP FD791
One of the most common questions in the forum is comparing the 422 to the 425-

Today i am bush hogging my hill which is about 12-14 acres and has some gentle long inclines and some pretty steep stuff.

As i lug my way up even the smallest incline with the bush hog running i often wonder what difference that 3 hp would make while mowing this area. The 422 is SEVERLY underpowered when mowing anything other than a flat area.

I have to make many many many trips for long distances with the PTO off in order to crawl up some portions of the hill just so that i can mow down hill.

It would be a great test to have someone with a relatively new PT 425 come with their machine with 48" brush cutter and run in the same area to see what the differences are apples to apples.

It would be very interesting to see what differences if any there truly are in this application.

In my mind i always think that i should have spent the extra dough but cannot really know and would not want to spend the extra for no additional power.

Any thoughts???

Surely there are enough people in the forum to fund a day trip for someone to compare the two models somewhere where there is a hill and some grass.......
 
   / Proposal for 422 vs 425 shootout #2  
Some of the things I did to my 422 was make sure at the carburetor that the gas is opening up all the way and you can set the governors up as well. I'll bet I gained 3 more hp when I did this.
 
   / Proposal for 422 vs 425 shootout #3  
What are you cutting? It makes a big difference on my PT-425.
 
   / Proposal for 422 vs 425 shootout
  • Thread Starter
#4  
mostly clover, grass, weeds and the occasional 2' high sappling. It is horse pasture that we rotate with other pastures. We typically mow it about 6"-9" high a couple weeks before we turn the horses into a new pasture to get rid of any lush growth that could cause grass colic in one of our mares.
 
   / Proposal for 422 vs 425 shootout #5  
How tall are the grasses and weeds you mow? If I am mowing old pasture gone to seed with the PT-425, I go at a crawl. For that stuff, I normally use my 35 HP Branson. It is much faster, and has a 6' cutter as well. Even it requires dropping into 3rd or 4th gear (out of 12) if it's thick and steep.
 
   / Proposal for 422 vs 425 shootout
  • Thread Starter
#6  
My biggest problem is simply getting the 422 to climb the hill. I wouldn't dream of actually trying to cut grass while climbing.

I have found that if i traverse the steep areas with the wheels inverted that it works just fine. It would just be nice to be able to go up the hill with a bit more umph.
 
   / Proposal for 422 vs 425 shootout #7  
Forgive me for bringing this up, but it almost sounds as if you aren't letting up on the pedal as the hill gets steeper and the load on the motor increases. Please confirm that you understand that the pedals are a transmission control, and that right pedal up (almost centered) is the lowest range, while right pedal down is the highest range.

The normal procedure is to let up on the right pedal if the engine rpms drop even the slightest bit. With a very steep slope, the pedal will be nearly all the way up (almost centered) and the machine should creep up the hill without lugging the engine--even while mowing.

Sorry if I just stated what is obvious to you, but someone in one of the other forums was having similar problems with his hydro tractor, and not knowing how the pedal operated turned out to be the problem. Your description of what your PT-422 is doing sounds quite like what he was going through.

Please confirm one way or the other.
 
   / Proposal for 422 vs 425 shootout #8  
</font><font color="blue" class="small">( My biggest problem is simply getting the 422 to climb the hill. I wouldn't dream of actually trying to cut grass while climbing.)</font>

Something sounds wrong here. I haven't found a slope yet that my PT422 wont climb. You keep the throttle wide open, choke off, and let up on the treadle enough to keep engine rpm's up, you shouldn't have a problem with any slope until you actually start sliding on it.
 
   / Proposal for 422 vs 425 shootout #9  
I've also found that I have better climbing ability before the hydro oil gets real hot...I'm guessing due to the "thickness" of the cooler oil versus when it thins out a bit at a higher temp? I too have several slopes and rarely cannot climb any of them(and that's usually due to wet grass) and I can normally mow up them too. The steepest of them does require a downhill cut though.
 
   / Proposal for 422 vs 425 shootout #10  
I wondered myself about getting a lower profile wheel and tire or just a lower profile tire. Wouldn’t this help in giving the 422 more uphill torque. I know less ground clearance, less speed, but more torque.
 
 
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