Yanmar RS1200 Tiller Question

[careyo63]

The key to that though is torque though. that's what does the work not HP. I am sure that v twin would bog and die hooking a tractor sized tiller to it.

And your estimations are a bit off I have used a 4 foot tiller with a 20hp PTO tractor and it easily tills the soil and way less than full throttle even.

Torque here is the key to doing the work and these diesels have tons of that. I have a 20ish horsepower riding mower that 42" cut there is no way even set to the highest setting that it could go out through some of my fields and cut the same grass that my tractor cuts. even if I put the 6ft (72") finish mower on and not use the bush hog so we compare apples to apples with finish style blades and cut. My 20HP pto tractor wins hands down

The same exact reason I bought my YM2000. I had a 21hp. Kohler and Craftsman had a problem it had to address for the way they rated the Eng. Hp.. I believe it had a 42" cut and in tall grass it worked real hard with multiple passes needed. And then the deck couldn't handle it. I was replacing the complete spindles in 2yrs. with the deck cracking etc..

 

[California]

I agree a YM147D won't run a RS1200 48" tiller. But a comparison to a V-twin gasoline engine isn't a good comparison either.

Clemsonfor has it right, these little Yanmar diesels are torque monsters different from anything with a gasoline engine. The gas engine is matched to mowing, with good horsepower at near full rpm. The diesels in contrast have more and more grunt as rpm gets pulled down by heavy loading, a very different profile.

One point of reference: 53" RS1400 has a decal on it showing it is specifically intended to match YM2000 which has only 20 pto hp. But YM2000 feels like its torque curve is flat, same torque, from 2200 engine rpm clear down to maybe 1500 rpm. I think its peak torque is at 1800, so it gets stronger as the rpm is dragged down from normal pto rpm. No small gasoline engine is going to have a torque profile like that.

 

[Jtullis13]

I agree with Clemsonfor, CareyO, and California. I have a 22hp Kohler with a 42" deck and it struggles on tall weeds at times. The HP is a number to look at, but so is the torque. HP is how fast it will go while torque is true reason it gets to where it's going. My 2210d runs a 5ft tiller with ease most of the time. Only time it doesn't is when I bury the thing deep in virgin soil.

 

[clemsonfor]

The same exact reason I bought my YM2000. I had a 21hp. Kohler and Craftsman had a problem it had to address for the way they rated the Eng. Hp.. I believe it had a 42" cut and in tall grass it worked real hard with multiple passes needed. And then the deck couldn't handle it. I was replacing the complete spindles in 2yrs. with the deck cracking etc..

yep my 42 inch I think its 15 or 18HP farm lawn mower takes multiple passes or slower or smaller passes to have a good cut. And I replace spindles every year or two on the thing. It just has no torque and the belt makes it worse with the slippage as there is no direct connection to the engine but this is probably necessary to aid in the motor staying in its torque ban, allowing for some slippage.