Hydro question

notjustair

Well-known Member
Zero turn mower - separate hydros for each drive wheel mounted in the same compartment as the engine. Should the fans on the hydros pull air across them to cool or blow air over them to cool? Hydros are mounted on the side wall opposite of each other so circulation is only over the pulley end and sides.
 
Probable makes a big difference, depends on the model and manufacturer. Assume you're putting this back together, I'd go ask dealer or find identical model, and take a close look at rotation.
 
What is your real question?

It sounds like you've removed the fans and are now trying to figure out whether they're upside-down or not. Flipping the fan over doesn't change the direction the air blows. But you do need the concave side of the blades facing towards the direction of rotation.

Take a look at the ZTR transaxles on this page. They all have the fan blades facing to blow air downward on the unit.
Hydro Gear transaxles
 
I have two of the same mowers. One was supposed to be a cheap parts machine but it only needed a $26 part and it works great. It has a bigger deck so I'd rather use it.

Since I have gotten it going I can mow about half the yard and then the left hydro gets hot enough that it starts to fail. The other one has never done it. I looked at the other one and it has one fan blade each way (one blows air on the hydro, one pulls air over it and blows it away). I don't know whether this is because the engine is smaller in it and doesn't heat up the compartment as much or whether it is supposed to be different. The one on the big mower has both fan blades set to pull air across the hydros but the left hydro is right beside the cooling fins on the twin engine.

The hydros are opposite from each other so I suppose it is feasible that the fan from one blows air to the other, but they are a foot apart and it seems unlikely.
 
It seems unlikely the transaxle is dropping out just because the airflow is backwards.

For your machine which has its fans running in opposite directions, are the input shafts running in opposite directions on the two transaxles? Is it possible one machine just has one fan installed backwards? Are you sure the airflow is reversed between the two?

If you're proposing to reverse the fan flow on the failing transaxle, the only way you can do that is to buy a different fan. I think you'll find there's only one fan available for that model transaxle.
 
Logically speaking, the fan would require some type of ducting to pull the air across the hydro. Blowing directly on it would NOT require ducting. So, as I see it, the fan blowing on the unit would be the correct way, trying to pull from it would simply not work, as you have already discovered.
For some "verification," try this: run any fan and put your hand in the airstream in the direction that it is blowing. You feel the strength of the air stream. Now move your hand to the other side of the fan. You will not feel the air stream being pulled in to the fan to any great extent.
As further proof, note that the unit with air blowing on it stays within operating temperature. The one that is trying to pull air across is getting too hot.
You have either the wrong fan or the wrong rotation of the fan motor. Reversing the polarity on that fan may be the fix you need.
 

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