721d Over heating think found problem need help

[BWH]

You have recieved a lot of good thoughts of how to solve your heating problem. In my opinion the first should be checking for sure that it really is heating up and not just a faulty gauge or sending unit. This can be checked by geting the MFG temp for mid range then remove the sending unit placing it in a bowl of heated water of a know temp using a second thermometer to check the calibration while still connected to the gauge. I have a 721 Grasshopper gas and even during this hot summer on a 100 dg. day it would rarely get past mid range never out of working range.

 

[alford35]

Its been a while since I posted but did finally manage to figure out why the mower was over heating. A engineer from Paducah KY had been informed of the problem and he managed to fabricate some kits to help the problem. The shroud/screen that covers the radiator doesn't keep clippings out of the fins so it continues to build up with small debris over time. I bought my mower used and was informed to blow air through the radiator by members here and also from my local repair guy. I was able to see particles coming out of the radiator after mowing when I blew it out but had NO idea just how much junk was trapped in there. I literally ran water through the radiator for an entire day before all the particles were finally removed. It has never over heated since the long thorough exterior cleaning. Blowing it with an air hose after a couple of sessions.

The engineer basically made three metal sheets that help keep clippings from entering between the screen and radiator. One piece on each side and one that slides up under it that is attached to the bottom of the seat. The kit hasn't been that helpful on windy days as I still have to clean off the front of the radiator after a few acres but the temp goes down immediately after rubbing the clippings off.

So its just a design flaw with the screen that doesn't keep everything from being sucked into the fins. An extremely good cleaning took care of the problem along with regular blowing it out throughout the season has kept the problem from returning.