Weird surge in RPM’s when turning.

[Granny’s old mower]

Hey guys,
I’m new here, of course.
Recently my granny had pasted away, and my father gave me her old
KUBOTA TG1860 Diesel. I have used this lawnmower many of times and have done most of the maintenance on her as well. But she has sat for about a year and when I finally got her home I did some much needed maintenance. Changed the oil, Air filter, flushed out coolant system. And changed all the belts. (The belt on the motor was the original one from 1998.) it was the cause of it overheating when I first got it not to long ago.
it has been doing fine all summer long until the other day. When I turn the mower it loses power and almost dies. It does have power steering but it’s electric not ran on a pulley. It’s weird and I have checked all the electrical connections that are on the mower.
If ya can help id greatly appreciate it

 

[kirkawilson]

Sounds like a similar problem here? TG1860 stalls and then wont turn over

 

[Jerry/MT]

Hey guys,
I’m new here, of course.
Recently my granny had pasted away, and my father gave me her old
KUBOTA TG1860 Diesel. I have used this lawnmower many of times and have done most of the maintenance on her as well. But she has sat for about a year and when I finally got her home I did some much needed maintenance. Changed the oil, Air filter, flushed out coolant system. And changed all the belts. (The belt on the motor was the original one from 1998.) it was the cause of it overheating when I first got it not to long ago.
it has been doing fine all summer long until the other day. When I turn the mower it loses power and almost dies. It does have power steering but it’s electric not ran on a pulley. It’s weird and I have checked all the electrical connections that are on the mower.
If ya can help id greatly appreciate it

Does it do this when the fuel tank is full? If the tank isn't baffled and you make a hard turn you could uncover the fuel pick up with a low fuel level. Otherwise I'd suspect some restricred fuel deliver. Is the tank clean of sludge?