Ive gotta question

   / Ive gotta question #1  

chromecrow

New member
Joined
Jul 16, 2003
Messages
13
Location
Ford, KY
Tractor
John Deere 755 2WD
I have noticed that a neighbor of mine seems to have his tractor running at a relatively low rpm while he is bushhogging. I have listened carefully and it seems that the blades on the bushhog are chopping at the same speed that mine spin. However I have to run my tractor wide open (3100 rpm) to acheive the proper pto rpm. I have noticed this on other bushhogging tractors as well. Anybody know what is going on here? Oh yea, my tractor is a JD 755 and my neighbor has a MF 35. It is a gas tractor i believe. the other tractors I have observed are also older models. /forums/images/graemlins/confused.gif
 
   / Ive gotta question #2  
Hmm - I'm not familiar with the PTO speeds on those, but is it possible that it is running a 1000 RPM PTO? I know a lot of the tractors used internationally have 1000 RPM PTO speeds, so maybe that Massey is geared for it, too? /forums/images/graemlins/confused.gif
 
   / Ive gotta question #3  
The pto speed on the Massey is most likely 540. They tend to run a couple hundred rpm lower than JD at least on 451MF about 1900rpm to reach 540 and about 2400rpm on my brothers 5310 JD to reach 540. My dads 135 Massey (gas) does it at about 1200rpm.
 
   / Ive gotta question #4  
The RPM for "rated" PTO speed on the JD 755 is around 3200.

Different tractors can require different RPM for the rated PTO speed. It is a matter of what RPM the engine gets it's best HP/torque. The gearing in the PTO is designed to work with that input to provide the standard 540 RPM output at the rear PTO.

One of my concerns when I first bought my 755 was that it required such a high RPM to get the rated HP. Most other CUTs at the time were in the 2600 to 2700 range with some as low as 2400. But I was assured that the engine was designed to run at the higher RPMs and it has for many years.

You should run your PTO driven implements at the RPM specified for your tractor to get the rated PTO speed.

Jeff
 
   / Ive gotta question
  • Thread Starter
#5  
I guess you guys are right on the money. It just got me studying when I could see his tractor puffing smoke rings while mine was running wide open. Thanks for clearing it up. 755inNY, I would like to hear about your 755. What do you do with it, how many hours, any problems? Mine has 285 hrs, I use it to mow and clear snow. I started bushhogging with it last year and I have done some minor excavating. I bought it new in '96. It is the "Mighty Tractor"
 
   / Ive gotta question #6  
My little Mitsubishi has a 3 speed tranny for the pto. I can get the 5' bush hog up to a pretty high speed in second gear running the engine at 1600 rpm which seems to be right near the maximum torque speed. Top hp is at 2250 which I can't reach running the tractor in ninth gear carrying an implement like the hog behind. The old 6' towable rotary mower had to be run in 1st gear just to get the blade up to speed, at that you couldn't start out with the mower and tractor at the same time and the throttle had to be wide open. The book said that was pretty close to 540 on the pto. Some of those old tractors never saw 2000 rpm in their wildest nightmares. /forums/images/graemlins/wink.gif
 
   / Ive gotta question #7  
The Massey PTO speed is about 1/2 the max engine RPMs - just the way they are geared. If you run an old Ford, Massey or IH at or near full throttle you will be spinning something well over 540 RPM, that is why your neighbor runs so slow. He also may be trying to achieve the perfect groundspeed for bumps etc, most tractors of that vintage have no low range, so 1st is pretty quick for rough ground. My 47 ford has so much torque just off idle that I sometimes run the cutter well below 540 - still cuts fine.
 
   / Ive gotta question #8  
<font color="blue"> 755. What do you do with it, how many hours, any problems? </font>

chromecrow,

I bought my 755 new in 1986. It has around 1200 hours on it.

Primary use is mowing. I have about 1.5 acres of lawn to mow and 3 acres of pasture. The pasture gets mowed about every 4 weeks in the summer. I also use the 755 to clear snow in the winter. I have a 7' 3PH mounted blade facing forward. I pull the snow to the end of my 75' driveway and use the FEL to pile it off to the sides.

The 755 has been used for a variety of other misc. duties. Moving stone, dirt etc. for various projects, post hole digging, bush hogging, moving trailers, digging, carrying etc. both on my property and my neighbors.

In that time I have replaced the front tires, the water pump (twice), muffler, battery, glow plug relay, the tachometer and cable (at about 800 hours) and the electro magnet for the PTO lever. The engine and hydro transmission have performed flawlessly.

I have replaced the belt on the MMM (after more than 10 years of use), the bearings in the gauge wheels, the antiscalp rollers, the belt tensioning pulley assy (my fault the pivot arm zirk fitting was not very accessible and I did not keep it properly lubricated), and the tensioning spring (seems to break every few years probably due to fatigue).

I replaced the bucket on the FEL last year (after market as JD no longer offers the bucket for the 52 loader). I had to replace a hydraulic hose 4 or 5 years ago when a fitting broke during use.

That's all I can think of. The tractor has been a real work horse. The tractor has never been garaged. It sits outside, uncovered, year round.

But.........I just ordered a new 4310 and the 755 will be traded in.
 
 
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