Changing Gearbox Ratio on a Brush Hog/Slasher

Brad V

Member
I have a Tea20 tractor and use a 4Foot Brush Hog/Slasher with a 1:1.93 gearbox ratio.
I used to use 3rd gear to do all my cutting and it works fine but found the tractor speed too slow and 4th gear at the same revs as a quick path to an early death.
I have flat paddocks and found that I can cut in 4th gear reasonably well at very low revs plus fuel consumption drops dramatically but the cut is not quite as good as what 3rd gear does as the cutter is not turning at the correct speed.
My question is has anyone tried the 1:2.83 gearbox ratio which should speed up the cutter and maintain the low revs and great fuel consumption?
Regards
Brad
 
Basic law of the universe states that you get
nothing for nothing . So by increasing the spin rate
of the cutting blades you must also increase the
load on the engine , this will probably also require
the engine to work at a higher rpm and so increase
fuel consumption .
 
I know that these tractors in top gear and at 1500 rpms are moving along at a frightening speed and a person brush hogging would almost certainly be killed, but the revs I am using are so low (I must connect my dwell meter to see my actual revs) that I am not moving any faster than my 15.5HP ride on mower flat out.
I don't think that my engine is turning more than perhaps 700rpm's and it does feel safe and it does a pretty good job. The engine runs great and does not miss abeat or heat up.
I must say that my slasher has been setup as per John(UK)'s instructions (angled with puncture proof rear wheel and sharp blades) and believe it or not it is safe.
If I felt that it was unsafe I would not risk my life.
Regards
Brad
 
You don't say what tractor you are using. But if 20 or 30, sounds like you need an over/under, Hupp or Sherman. I have & use a Hupp and yes they really do save fuel if used properly. Back in the day we used to rake hay in 4th. gear (TO20)using Ferg. rake. What an amazing machine.
 
When using any PTO driven implement with a tractor, the PTO speed at which it is designed to operate is 545 PTO rpm which corresponds to 1500 (or 3/4 throttle) on your tractor. The Engine develops maximum torque between 1200 and 1700 engine rpm. You don't vary from that and it will operate just as it was intended to do. If you are having problems with excessive fuel consumption then you should check the settings of the Carburettor and make sure that the Air Cleaner is clean and clear and serviced daily (change the oil daily) If you do adjust the Carburettor never set the main jet less than 1 turn open in an attempt to make the tractor more economical or you will burn the exhaust valves. If you need the information about setting the carburettor, email me and I will send it you. There is more than one type of main jet used on these Carburettors, so the adjustments are not all the same.
Using 4th Gear is far too fast for any PTO mower work and should be discouraged. The problem will be if the crop you are cutting is of sparse growth. The mower will be set-up from the manufacturer with a gearbox ratio to handle most conditions. Below 1000 rpm the Engine Governor will not always operate properly. John(UK)[email protected]
 
Ken. He has a TEA20, not TO20 or 30. We are in Australia and the Hupp and Sherman are not an option and not available here or on the TEA20.
 
I have a Tea20 which is the 85mm bore Standard Engine from England approx 28.2HP.
Some time back I was looking into the Hupp/Sherman/Ferguson Epicyclic gearbox option but here in Australia and now in the USA I would most likely find a Unicorm before one of these could be found in good working order.
Regards Brad
 
My tractor has been tuned to perfection as per your instructions quite some time ago and runs like a swiss clock.
The way I cut my paddocks at the low revs I use in 4th gear my fuel consumption believe it or not varies from 2.4 litres per hour for light work to 2.9 litres for heavy work.
I have one paddock approx 4 acres that at one stage using 3rd gear used to use 18 litres of fuel but now using 4th gear and low revs I can cut it in 1hr and 40 mins and use 4litres of fuel.
Hard to believe but true.
Next time I cut the grass I will fit the dwell meter on to see exactly what revs I am running at.
Regards Brad
 
Brad. I've been looking for a good Ferguson Epicyclic gearbox for twenty years and can't find one. It appears they were more common in the southern States (of Australia) where Fergys were more frequently with a rotary hoe.

Why is fuel flow so critical? I'd sooner burn a bit more motion lotion rather than stress the engine and risk over heating. That is why you have four gears.........

Bob in Oz
 
(quoted from post at 11:55:54 01/10/13) Brad. I've been looking for a good Ferguson Epicyclic gearbox for twenty years and can't find one. It appears they were more common in the southern States (of Australia) where Fergys were more frequently with a rotary hoe.

Why is fuel flow so critical? I'd sooner burn a bit more motion lotion rather than stress the engine and risk over heating. That is why you have four gears.........

Bob in Oz
I rebuilt my engine in July 2011 and am surprised as to how good the engine is but it was thirsty until I followed John(UK)'s carburettor settings advise.
One thing I did not change was the radiator which is a Coventry Radiator which must be the original radiator but it still looks brand new and it never over heats (Touch wood).
I find it hard to believe that this could be the original radiator, I know that they were the very best quality in their time. If it had been replaced it may be a NOS item as I doubt that the eg Ebay Radiators available would be the same quality as the originals.
In relation to the fuel use, perhaps I am just mean and trying to stretch my dollars a little further as I am getting older.
I do like getting something for nothing but it rarely happens.
Reality is that I find mowing/slashing/Brush hogging boring and try to get the job done as quickly as possible.
Having said the above I don't take chances and risk my life or the life of others around me when on the tractor.
Regards Brad
 
Brad.

Keep your anti freeze at 50% plus 50% water, change coolant each two to three years and I guarantee that Coventry Radiator will still be good and in service long after you are pushing up daisys! Coventry Radiators are the very best you can get. At least twice the weight of the after market product.

My TEA20 radiator is five months short of 60 years of age and in the same perfect condition it came out of the factory, which is more than I can say about it's owner!

Bob in Qld
 

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