Mowing and PTO speeds

[wheelbuilder]

The mower that came with my 1502 is rated for 540 rpm. The Bolens doesn't quite get there in the PTOs first ratio, only 454 rpm. It mows ok there for me. I've been playing with using the second PYO ratio, which would give 724 rpm at the rated engine speed, but slowing the engine to 2000 rpm for the required 540 at the PTO. I can tell the engine is working harder, as there is a slight difference in the exhaust color, (it slightly visible, compared to pretty invisible ) but that's it. The mow quality seems somewhat better, I think it gets better lift on the grass.

Should I not sweat the extra work the engine is doing, or go back to the lower ratio at rated speed ? Is there a better way to tell if I'm working the engine too hard ?

 

[Ilikeurtractor]

If the high temp light comes on then you're obviously overloading the engine beyond design capacity assuming the cooling system is functioning as intended. If it doesn't I wouldn't worry too much about it.

 

[wheelbuilder]

I'm going to see if I can find a non-contact thermometer and get an actual number for the temp. and compare the two. If nothing else it will let me make sure the temperature light is indicating correctly.

 

[TractorGuy]

https://www.tractorbynet.com/forums/parts-repairs/414290-digital-photo-tachometer.html

 

[Ilikeurtractor]

I'm going to see if I can find a non-contact thermometer and get an actual number for the temp. and compare the two. If nothing else it will let me make sure the temperature light is indicating correctly.

Compare the two? Unless your tractor has an aftermarket gauge the 1502 should only have a high temp on/off light. In order to test that, the thermo switch in the cylinder head will have to be taken out and placed in oil heated to 230°F (or thereabouts if memory serves me) using something like a candy thermometer and see if it switches (closes the circuit), unless you can get the light to activate by overloading the engine with your mowing which is entirely possible I suppose. You didn't mention the light coming on so it will be hard to compare if you can't.

 

[wheelbuilder]

Compare the two? Unless your tractor has an aftermarket gauge the 1502 should only have a high temp on/off light. In order to test that, the thermo switch in the cylinder head will have to be taken out and placed in oil heated to 230°F (or thereabouts if memory serves me) using something like a candy thermometer and see if it switches (closes the circuit), unless you can get the light to activate by overloading the engine with your mowing which is entirely possible I suppose. You didn't mention the light coming on so it will be hard to compare if you can't.

Sorry, I meant get a number with the thermometer mowing at the lower PTO ratio and then at the higher. I've only got the idiot lights on the tractor. That's fine with me, I like that simplicity. I may test the switch the next time I change the coolant.

 

[Ilikeurtractor]

I would always recommend at least checking to make sure the bulb works by jumpering the wire to ground with the key on at the connection to the thermoswitch which will also test the wiring at the same time. Since the temp light may never go on in a tractor's lifetime (at least these tractors anyway) it is entirely possible something is defective in the circuit and it won't be noticed, most likely the bulb. If this test passes then the only thing that could have a failure is the thermoswitch. All of the switches I've tested which were only a couple have worked so they seem to be fairly reliable after all these years.

 

[wheelbuilder]

Good point, I will do that as well.

 

[wheelbuilder]

So I checked the hi temp circuit, the bulb and wiring are ok.

I checked the temp mowing for 1/2 hour in PTO '1' at 2700 rpm on the tach. The highest temp I could read on the radiator hose and radiator was about 185. I then mowed another 1/2 hour in PTO '2' at 2000 rpm on the tach to get 540 at the PTO. I got the same temp on the radiator hose and radiator.
Granted this is a finish mower making a pretty light cut, but I'd say it isn't working any harder.
If I can find something heavier to cut I might do some more checking if anyone is interested.

 

[Ilikeurtractor]

Glad to hear the good results!