Why does my husqvarna running slow?

SOURCE: I have a YTH1542 husqvarna riding mower. Will not stay running

make sure the small vent hole on top of the gas cap is not clogged. Mine did the same thing and then I found mine was packed with dirt.

SOURCE: throttle control won't work after i cleaned the

Hi again Ed,
Starting at the carb throttle shaft, your linkage rod (with tiny spring wrapped around it) should be connected directly to the governor's arm. If there's more than one hole in the arm, connect the rod in the upper-most hole.
Now, at the base of the governor's arm is another hole (possibly on a tab jutting from the arm). The main governor spring should be hooked in this hole and then back to the sliding throttle control that moves when the lever on the dash is moved. (This one definitely has a tab and hole.)

The choke cable end hooks directly on the choke shaft and it has intuitive movement. Verify that the choke butterfly closes and opens relative to the cable control on the tractor's dash.

To insure that we only do this procedure ONCE, and we get it right the first time, let's set the internal governor to base-line at this time.

With everything bolted back up, move the throttle control lever on the tractor's dash to full throttle. Then get a 3/8 wrench and a slotted screwdriver and locate the round governor shaft coming out of the engine block. The governor arm attaches to this with a clamping-bolt. You will notice that the round shaft is slotted for a screwdriver as well.
Loosen the clamping bolt slightly with your 3/8 wrench, insert your screwdriver and rotate the round shaft clockwise until it stops. (It has VERY little travel, so turn it both ways to verify that your are at FULL clockwise position.)
Hold screwdriver there and move the governor's arm in the same (clockwise) direction until the carb's throttle is set to WIDE OPEN throttle. Still holding the screwdriver clockwise, retighten the clamping bolt with the wrench.
Next, move the throttle lever on the dash of the tractor to idle and back to full several times and observe the carb's throttle shaft, it should come down from full throttle to idle and back again freely.

Start the engine and be prepared to shut it off if it over-revs.
If it doesn't over-rev, your base-line settings are correct.

By bending the tab on the sliding throttle control (the one that has the main spring attached) you can now increase or decrease spring tension and change top speed of the engine. Do this in small increments and if you have a tachometer for single cylinder's set top speed to 3400-3600 RPM.

Sorry this is lengthy, but as mentioned above, we only want to do this once.

Hope this helps, and feel free to ask away if you need more info!
Dolf-

Testimonial: "thanks for the advice , i got the mower running well now. ed"

SOURCE: I have a Craftsman Model

It seems like the valves are not working too well, backfire indicates that the valve is not closing properly and the fuel is getting pushed past the the valve and igniting in the hot exahaust pipe. It is possible that this tracktor is overdue for an oil change, an oil change would prevent damage to the valves and help cool the engine. I think your problem could be due to low oil level either currently or in the recent past.

As you explained it runs normally on a cold start and then gives troubles as it gets hotter, I think it is overheating and new oil will help keep it cool and get it running smoothly. However it is possible that the valves are damaged slightly, this is confirmed if the tracktor is low on power.

I think it might also be possible that the carberator is a bit stuck/gummy. Clean out the carberator and airfilter.

Take care!
damnor01