Got the 646 out of the moth balls

[Harry]

I pulled the big tire 646 out today and connected the rear mowing deck. Made a few passes in the swamp driving through water as I cut the 12” high grass and weeds. After about 30 minutes the hum of the rear deck slowed down as did the speed of the GT. I slowed it to idle moved the pto to neutral and drove away fine with no lack of speed. Again slowed to idle started the mover again and drove away. In a very short time again them mower slowed as did the speed of the GT. I drove it back to the shop and checked the oil reservoir. Oil was circulating fine and with my infrared heat gun checked the oil temp, which was 140 degrees F. No apparent oil leaks were observed. I have read where the oil from the pump goes to the pto first then to the tvc. Maybe the motor on the mower is going which I believe are nla. Anyone have any ideas what to check next. Harry

[myerslawnandgarden]

I pulled the big tire 646 out today and connected the rear mowing deck. Made a few passes in the swamp driving through water as I cut the 12” high grass and weeds. After about 30 minutes the hum of the rear deck slowed down as did the speed of the GT. I slowed it to idle moved the pto to neutral and drove away fine with no lack of speed. Again slowed to idle started the mover again and drove away. In a very short time again them mower slowed as did the speed of the GT. I drove it back to the shop and checked the oil reservoir. Oil was circulating fine and with my infrared heat gun checked the oil temp, which was 140 degrees F. No apparent oil leaks were observed. I have read where the oil from the pump goes to the pto first then to the tvc. Maybe the motor on the mower is going which I believe are nla. Anyone have any ideas what to check next. Harry

Yep. my guess would be mower deck motor, a common problem.

Bob

[DavidBarkey]

I pulled the big tire 646 out today and connected the rear mowing deck. Made a few passes in the swamp driving through water as I cut the 12” high grass and weeds. After about 30 minutes the hum of the rear deck slowed down as did the speed of the GT. I slowed it to idle moved the pto to neutral and drove away fine with no lack of speed. Again slowed to idle started the mover again and drove away. In a very short time again them mower slowed as did the speed of the GT. I drove it back to the shop and checked the oil reservoir. Oil was circulating fine and with my infrared heat gun checked the oil temp, which was 140 degrees F. No apparent oil leaks were observed. I have read where the oil from the pump goes to the pto first then to the tvc. Maybe the motor on the mower is going which I believe are nla. Anyone have any ideas what to check next. Harry

After about 30 minutes the hum of the rear deck slowed down as did the speed of the GT.

Yes inline , with the pto motor first .Remove the flow control valve in the diagram . If the motor was bypassing (going bad) the traction motor should get more oil easier . The fact that it is slowing the tractor down tells me the oil pressure and volume is being held back . This says to me that something on the deck is seizing up or the deck is getting so wadded up with grass the blades wont turn freely . I would first check the deck for obstructions, bad bearings ,ect. then do a load test on the deck again and check for spindles, pulleys , motor ect. heating up .

[Harry]

There is no flow control on this GT. The deck spindles were serviced two years ago with very little use. The deck was clean underneath when I attached the deck to the tractor. I did notice a lot of debris coming out of the deck when mowing but I’ll take a look to make sure. I may have picked something up when mowing through high growth. This was a used deck that I picked up cheap and checked it out before painting it. I have read about the motors wearing out, so that could be the situation. I’m not to worried about it it’s not my only mowing GT. I still have to attach the deck to the 444. As usual to many irons in the fire for Harry. Harry

[MattA]

Maybe add a quart of thicker oil to the hydraulic tank or an auxiliary cooler?

[Harry]

I drove the 646 with the big boots and 20hp Honda engine out to the swamp today. This GT is a beast and goes through the water and mud with no problem. I used the rear mowing deck with no problem. I think the first time I was just moving to fast in the tall grass. Harry