After solving the no start when hot problem of my buddy's 801 (could be an 821?), I went on to tackle the overheat issue it's had since he bought it 13 years ago.
(I read the latest overheating thread first)
At first I thought it might have either a 190 degree thermostat, or a thermostat which didn't open fully, impeding the coolant flow. There was no thermostat in the thing, which told me that whoever had this tractor before him had the same problem.
Further confirming that someone else had the same problem was the spark plugs show it running just a tad rich, so it's not a lean mixture.
It runs at the top of the green when he's using the finish mower deck. If he runs it in any gear other than 1st in low (has the hi/lo "S" transmission) it goes into the red & it is overheating, it's not an indication problem.
The water pump is old, but works fine. The radiator is unobstructed. The block is unobstructed. (We ran water through both & it came out as fast as it went in.)
The coolant came out bright green, looking like new. On occasion he's added small amounts to it, but other than that it's had the same coolant that came with the tractor 13 years ago. I've seen coolant from cars which had leaky head gaskets & it was brownish looking from combustion gas.
I was thinking perhaps it could be overheating due to advanced timing. We didn't have a timing light, so we put a cigarette paper between the points. I slowly turned the engine until my buddy could pull the paper out. We checked the timing mark & it was on 3 degrees BTC. (It's supposed to be 4 degrees BTC @ 45-475 rpm & 24 Degrees BTC @ 2200 rpm.)
But even if we had a timing light we wouldn't know what the true rpms would be as the tach reads 950 with the engine off. The max RPM on the tach is 25-2600 rpms & he's never been ran it anywhere near that. I'm guessing that he runs it at about 13-1400 when he cuts grass, which is as fast as he usually runs the thing. On a 70 degree day that'll put it at the top of the green, right next to the red. On a 90 degree day it'll overheat.
I'm not sure how to check the timing without knowing the rpm's. The engine starts & runs good. Any suggestions?
(I read the latest overheating thread first)
At first I thought it might have either a 190 degree thermostat, or a thermostat which didn't open fully, impeding the coolant flow. There was no thermostat in the thing, which told me that whoever had this tractor before him had the same problem.
Further confirming that someone else had the same problem was the spark plugs show it running just a tad rich, so it's not a lean mixture.
It runs at the top of the green when he's using the finish mower deck. If he runs it in any gear other than 1st in low (has the hi/lo "S" transmission) it goes into the red & it is overheating, it's not an indication problem.
The water pump is old, but works fine. The radiator is unobstructed. The block is unobstructed. (We ran water through both & it came out as fast as it went in.)
The coolant came out bright green, looking like new. On occasion he's added small amounts to it, but other than that it's had the same coolant that came with the tractor 13 years ago. I've seen coolant from cars which had leaky head gaskets & it was brownish looking from combustion gas.
I was thinking perhaps it could be overheating due to advanced timing. We didn't have a timing light, so we put a cigarette paper between the points. I slowly turned the engine until my buddy could pull the paper out. We checked the timing mark & it was on 3 degrees BTC. (It's supposed to be 4 degrees BTC @ 45-475 rpm & 24 Degrees BTC @ 2200 rpm.)
But even if we had a timing light we wouldn't know what the true rpms would be as the tach reads 950 with the engine off. The max RPM on the tach is 25-2600 rpms & he's never been ran it anywhere near that. I'm guessing that he runs it at about 13-1400 when he cuts grass, which is as fast as he usually runs the thing. On a 70 degree day that'll put it at the top of the green, right next to the red. On a 90 degree day it'll overheat.
I'm not sure how to check the timing without knowing the rpm's. The engine starts & runs good. Any suggestions?