My Tractor Forum banner
  • Are you passionate about Tractors? Would you like to write about topics that interest you and get paid for it? Read all about it here!
1 - 2 of 2 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter · #1 ·
Thanks for your help ahead of time i have a husky yth23v48 iv changed fuel and filter and air filter also but when im driving with blades turned off it surges and backfires but when i activate blades she purrs like a kitten any ideas
 

·
Registered
'81 Gravely tractor, 50's 60's 70's 80's 90's Gravely tractors Various Honda Power equipment
Joined
·
539 Posts
A clogged slow jet or a clog in the low speed circuit of the carburetor, or a lean mixture down at lower speed fuel circuit.
When the engine is at high speed 'Unloaded' it is actually taking its fuel from the low speed circuit because the throttle plate is not open that far.
Once the engine is under a load, the governor opens the throttle plate further, then it will take more of its fuel from the main circuit-jet.
Most people think it only takes fuel from the main when at high speed, whether it is under a load or not, but that's not always true. Under a load it takes most of its fuel from the main circuit because the throttle plate is open further so the fuel comes from the main jet and nozzle but once it is not under a load the throttle plate closes off a lot and then it takes most of the fuel from the low speed jet and low speed passageways of the carburetor even though the speed is higher, the plate is not open that much further than it would be at idle speed.
The surging occurs when the engine can't get enough fuel to keep it running steady enough and begins to die down in speed, then right away the governor reacts to that and opens the throttle plate further to recover, causing the sudden surge, then the governor takes over again and slows it back down.
It will keep repeating that procedure over and over causing the surging effect until the engine is back under a load again and requires more fuel so the governor opens the plate further to maintain the engine speed and takes most of its fuel from the high speed circuit so it smooth-ens out.
 
1 - 2 of 2 Posts
Top