john deere vs yanmar engine

[deerefan]

quick question.....while deciding between the 990 and 5103, other than horsepower and size, I noticed the 990 had a yanmar engine and the 5103 had a john deere engine....which one is the better engine? I bought the 5103 b/c it was actually cheaper than the 990 and it seemed logical that getting parts for the j.d. engine would be a much easier undertaking.

 

[Dutch445]

Those 2 tractors, although seem similar, are quite different.
The 990 with the Yanmar, is only a category 1 3ph, and is much lighter than the 5103. 3175 lbs vs 4475. The difference in power is quite a bit, even though they both advertise 40hp tractors. Compact tractors seem to advertise engine HP,, while the JD utliity tractors advertise PTO hp.. big difference. 35hp vs 42 at the PTO. There's a good difference in size,, 121 cu in vs 179 .
as far as reliability, I would say they are both great motors.. the Deere engine is a PowerTech engine, which means down the road it can be rebuilt in the block, where the yanmar would have to be bored etc for a rebuild, but that could be decades away!
I would not say parts availability would be different due to the different tractors or engines,,,
besides ,
one is from Japan,
the other India!
/forums/images/graemlins/cool.gif

 

[deerefan]

as the old saying goes 6 one half-dozen the other!

 

[jcmseven]

I don't begin to know what Dutch does about this topic, but will share a couple of thoughts. I just traded (sold) my 3720 today for a 4520 I looked at last week. The main reason I did so was power. I am a power junkie, and the more, the better. I had a 4310, then went to a 3720, which was/is an awesome machine. I must admit, though, that the thing that sold me was the extra torque of the Power Tech engine. On paper, with the weight difference between machines, I would have expected my 3720 to perform as well as the Power Tech on hills, etc., but it fell slightly short. Not to say it is not powerful, it is, but I was quite surprised about the 4520 power. That said, Yanmar makes a bulletproof motor. I think they are the best small diesel engines in the world, bar none. My neighbor is tooling around on his 2000 hour 4410 without a hint of tiredness from the motor. The Power Tech has not built that reputation yet, but JD will stand behind its product. Those engines have been used in skid steers for awhile now in pretty heavy industrial applications. Personally, I doubt I will put thousands of hours on my machine, so the reliability issue may be moot. In short, I would choose the powertrain that fits your performance needs, as neither engine will leave you disappointed.

John M

 

[4120]

I recently purchased a JD4120, which has the powertech engine. I had an older 870 with a yanmar engine, it was rock solid. I have had nothing but trouble with the 4120 engine, between smoking black and white smoke, not starting right, not idleing right, 4 trips to the dealer, and it's still isn't running right, not to mention the other trouble i have had with tractor itself, if i had to do it all over again i would buy the 990 with the yanmar. Or go with Kubota. Hopefully i just got a lemon, cause if not, John Deere is falling apart!!