Is it really overheating?

[ghmerrill]

Okay, I'm about at the end of the trail one way or the other now. At this point I've *very* carefully mixed my coolant. I've flushed the radiator and the block (independently) both ways (top to bottom and bottom to top). I've got a new fan belt. I've got new radiator hoses. Based on seeing the flow during flushing, it's difficult to believe there is any constriction or obstruction. I've adjusted the clutch.

After about 30-40 minutes of bush-hogging (even in *very* light grass/weeds), the temp light comes on. So I stop the machine and (with great care), open the radiator. It shows 205 deg F on my handy dandy candy thermometer. It has not boiled over.

So ... what's the best hypothesis at this point? Looks like the sensor is faulty? In that case I'm inclined to install a real thermometer to tell me what the actual temp is. Hoye seems to have one.

Has anyone reading this installed one of those? What exactly is the "overheat" temp on a 1700?

I don't want to spend money on a water pump if I don't have to, but I'm thinking that this 4' rotary cutter is probably close to limit for one of these little machines. Any thoughts?

How much of a pain is it to install the water pump?

 

[ghmerrill]

Okay, I'm about at the end of the trail one way or the other now. At this point I've *very* carefully mixed my coolant. I've flushed the radiator and the block (independently) both ways (top to bottom and bottom to top). I've got a new fan belt. I've got new radiator hoses. Based on seeing the flow during flushing, it's difficult to believe there is any constriction or obstruction. I've adjusted the clutch.

After about 30-40 minutes of bush-hogging (even in *very* light grass/weeds), the temp light comes on. So I stop the machine and (with great care), open the radiator. It shows 205 deg F on my handy dandy candy thermometer. It has not boiled over.

So ... what's the best hypothesis at this point? Looks like the sensor is faulty? In that case I'm inclined to install a real thermometer to tell me what the actual temp is. Hoye seems to have one.

Has anyone reading this installed one of those? What exactly is the "overheat" temp on a 1700?

I don't want to spend money on a water pump if I don't have to, but I'm thinking that this 4' rotary cutter is probably close to limit for one of these little machines. Any thoughts?

How much of a pain is it to install the water pump?

 

[normde2001]

I would install a new sending unit and have a radiator shop clean and test that radiator. The light should come on at about 235 degrees; however 180-190 is a good operating temp for any water cooled vehicle.

 

[normde2001]

I would install a new sending unit and have a radiator shop clean and test that radiator. The light should come on at about 235 degrees; however 180-190 is a good operating temp for any water cooled vehicle.

 

[ghmerrill]

I think that at this point, here's my plan:

1. Get the water pump.
2. Since I have to pull the radiator to install the water pump, take it to a radiator shop at that point.
3. Install a new sending unit and a temp gauge.
4. Fill cooling system with the stuff that promises it will run 400 degrees (okay, may that's 40) cooler.

I'm getting weary of trying "point solutions" to this problem -- which is just costing me time and will end up costing me cummulative shipping costs for each one!! Time to bite the bullet and go for the systemic solution.

At that point I know I'll have a good cooling system -- and if it doesn work, I'll just have to put a different tractor under it . Or, since I really like this little beast, I could move on to something like a "total loss cooling system" where I mount a tank of water and spray it directly on the outside of the engine while running.

 

[ghmerrill]

I think that at this point, here's my plan:

1. Get the water pump.
2. Since I have to pull the radiator to install the water pump, take it to a radiator shop at that point.
3. Install a new sending unit and a temp gauge.
4. Fill cooling system with the stuff that promises it will run 400 degrees (okay, may that's 40) cooler.

I'm getting weary of trying "point solutions" to this problem -- which is just costing me time and will end up costing me cummulative shipping costs for each one!! Time to bite the bullet and go for the systemic solution.

At that point I know I'll have a good cooling system -- and if it doesn work, I'll just have to put a different tractor under it . Or, since I really like this little beast, I could move on to something like a "total loss cooling system" where I mount a tank of water and spray it directly on the outside of the engine while running.

 

[buppy69]

Water boils at 212 degrees. Add antifreeze + pressure and it boils at a much higher temperature. 205 degrees is not an unreasonable temperature. I'd just replace the sending unit.

Eugene

 

[buppy69]

Water boils at 212 degrees. Add antifreeze + pressure and it boils at a much higher temperature. 205 degrees is not an unreasonable temperature. I'd just replace the sending unit.

Eugene

 

[ghmerrill]

I would just replace the sending unit if I were confident that the engine with its thermosyphon would support the sort of work we need it to do. We will use this mostly for mowing, and for mowing only about two acres at any one time. But we'd prefer to not have to do that *too* slowly or in multiple stages.

I have the feeling that the mower I've got will be pushing the current engine and cooling system to its limits in the conditions that we typically mow (figure 90 degree weather, more or less). I'm guessing that even if I can get it to work reasonably well without adding the water pump, I won't have any margin of error left.

I should also be sure that the radiator is in fact clear and functioning up to its capacity. To do that, I need to pull the radiator and get it to a shop. Given that I have to do that and that I need to at least replace the sending unit, I'm inclined toward spending the extra money for the water pump with the idea that I'll do all that at one time, one shipping cost, one disassembly and installation, be done with it, and have the widest margin of safety I can get.

The old Massey (1958, 4 cyl Continental gas) we've been using for over 10 years also does not have a water pump and has never come close to overheating even under the most extreme conditions and on the worst days. But that engine is (nominally) 38 hp. This also inclines me to think that the overheating problem is in part a consequence of the tractor hp vs. what is required to drive this mower, and that the best way to address this is via the water pump.

 

[ghmerrill]

I would just replace the sending unit if I were confident that the engine with its thermosyphon would support the sort of work we need it to do. We will use this mostly for mowing, and for mowing only about two acres at any one time. But we'd prefer to not have to do that *too* slowly or in multiple stages.

I have the feeling that the mower I've got will be pushing the current engine and cooling system to its limits in the conditions that we typically mow (figure 90 degree weather, more or less). I'm guessing that even if I can get it to work reasonably well without adding the water pump, I won't have any margin of error left.

I should also be sure that the radiator is in fact clear and functioning up to its capacity. To do that, I need to pull the radiator and get it to a shop. Given that I have to do that and that I need to at least replace the sending unit, I'm inclined toward spending the extra money for the water pump with the idea that I'll do all that at one time, one shipping cost, one disassembly and installation, be done with it, and have the widest margin of safety I can get.

The old Massey (1958, 4 cyl Continental gas) we've been using for over 10 years also does not have a water pump and has never come close to overheating even under the most extreme conditions and on the worst days. But that engine is (nominally) 38 hp. This also inclines me to think that the overheating problem is in part a consequence of the tractor hp vs. what is required to drive this mower, and that the best way to address this is via the water pump.