Engine surging (?) when PTO is off

[Hanns]

Hello,

I have a 2016 Toro SS5000 that started acting up today. Yesterday I mowed, no problem. Today the engine sounds like it's ramping up and down whenever the blades are disengaged. When I try to move the mower, its motion also jumps with the RPM. But when the blades are engaged, everything works as expected.

Now I'm not the most mechanically knowledgeable guy out there, so I'd appreciate any advice. I would have thought it's an air/fuel issue, but it's strange that it seems to work fine when the blades are on. I did check the air filter, and it looks good.

Thanks!

 

[Hammermechanicman]

It is bouncing on the govenor because the idle circut is not working. When the pto is engaged the engine runs on the main jet high speed circuit.

 

[Hanns]

It is bouncing on the govenor because the idle circut is not working. When the pto is engaged the engine runs on the main jet high speed circuit.

Thanks for the info. From what I can find these circuits refer to pathways in the carb. So it sounds like the carb needs a cleaning.