Overheating YM1500

mszb · Aug 31, 2003

Recently when using my 5 foot EFM finish mower my tractor has been overheating. It does not seem to do it with my tiller or brush hog. I first flushed the radiator then refilled it with 25% antifreeze to water, but this has not helped. I have cleaned the screen and fan blades and tightened the belt. Am I just working it too hard or could there be another problem, clogged core, hoses etc? I think there is good flow because as the tractor cools the overflow tank changes volume rapidly. Any other ideas or am I just working it too hard in the Dog Days of August in sunny South Carolina?

mah · Aug 31, 2003

I would take the radiator to a shop and have it flow tested and rodded out if needed. I would also flush the engine block with the garden hose.

mszb · Sep 1, 2003

How do I flush the engine block? Stick a garden hose in the top hose and let it run out the bottom hose?

Bird · Sep 1, 2003

Matthew, that will work fairly well, if you are talking about putting the garden hose in the top radiator hose if you have the thermostat removed. If the thermostat is still in, cold water isn't going to run through it. In the old days, we used to flush the system on cars by simply opening the drain cock, putting the garden hose in the top of the radiator and leaving the water running slowly with the engine running. And of course, then they came out with fittings to go into the heater hose (which you probably don't have on a tractor unless it's a cab model) to "backflush" the whole system.

mszb · Sep 1, 2003

That sounds simple enough, I will give that a try and pull the radiator and take it to the shop. Thanks for the help.

rdam · Sep 1, 2003

There is no thermostat on the YM1500. There is no water pump on the YM1500. The system is a naturally circulating "thermosyphon" type system. Since there is no mechanical pump to move the water, the natural cooling (radiator) and heating (engine block) keeps the water moving. Antifreeze inhibits this process.

Have a radiator shop clean the radiator. Flush out the block as best you can from the top. Check to make sure that the pressure cap is working properly and has the proper pressure rating (7 or 8 pounds I think...Experts will advise). Run STRAIGHT DISTILLED WATER. If you are in an area that freezes, run 10% or 20% anti freeze ONLY IN THE WINTER.

Run the engine at 2200 to 2400 RPM when working. The higher rpm keeps a sufficient amount of air moving across the radiator which improves the efficiency of the "thermosyphon" system

Anti-freeze inhibits the proper and natural flow of the "thermosyphon" sytem. If you keep your tractor inside and/or there is no danger of freezing, forget the antifreeze. Also, try adding "water wetter". I have and it seems to help reduce water temps.

ALL of the previous information was obtained from other TBN members over the last 6 months. If it was not for the knowledgeable members I have encountered on this website, I'd be overheating too.

rrw1238 · Sep 3, 2003

I notice overheating whith mowers seems to be a frequent problem. Having grown up in the mountains of Colorado and around trucks I learned very young that when you are over heating the first thing you need to do is go to a lower gear. This causes the engine to rotate faster and circuilate the water faster there by disapating heat faster and generating heat slower. Overall result is is engine does not get as hot.
Just think about it like this if you are pulling something while walking and then decide to try running while pulling it you will have a harder time pulling it and your body will generate a lot more heat also.
Sometimes the desired results can be achieved by putting your PTO ina lower speed. sometimes better results can be achieved by shifting the tractor to lower speed or lower range. Try it you should notice a difference.
Back in the days when everybody was using CB radios I have over heard truck drivers complaining about thier trucks over heating and would tell them to try it. It never failed. They may have had years of experiance but they were not used to driving in the mountains and had never learned this. Remember slow and steady wins the race.
Ralph

pruntyc · Sep 3, 2003

I don't think the 1500 has a water pump so the engine running faster don't move the water any faster, if this is so. Also he should be running the PTO in the lowest speed when mowing anyway about 540rpm. Faster than that can damage the gears and cause it to overheat. Fact is other than tilling it should always be run in the lowest speed. And probably tilling unless the ground has already been tilled and just want to fluff it up some more.

gbirky · Sep 3, 2003

Dick has it right. No water pump. Also, run pto in 1st gear (540rpm) for finish mowers.

Using a lower gear will help in two ways. 1) tractor is moving slower, so not cutting as much grass with each engine revolution 2) if the engine is lugging down to lower than the engine speed with clutch in - the lower gear will increase engine speed moving more air through the engine, and keeping it cooler.

Soundguy · Sep 3, 2003

You can do a quickie radiator flow test yourself with the hoses off and the garen hose / bucket.

A decent radiator should be able to keep up with a 1/2" hose flow. If it is dribbling out.. there's your problem.

Soundguy