My harrier Hayter is only working at low revs and I don't understand why. There are some springs that seem to work the throttle at the carburation end near to the primer cold start. Are these springs self adjusting, in other words as the engine revs it automaticely moves the spings as needed? If I pull on one of the moveable spring levers it revs the engine but it tends to flucturate in the sound of the revs as if it is not getting the right mixture. Can anyone help point me to what is wrong with the mower. I change the oil regularly but I have never touched the carb. I regularly clean out the air filter sponge.
Thanks Chris

Chris Norris, July 2009

You could try undoing the anchor for the throttle cable on the engine side and adjusting the cable so that when you operate it, it will pull the linkage more.
I worked with these mowers for years and they were generally a pain even from new with some of them.
Try adjusting the throttle cable but check on the carb end that it is working the linkage when you operate the lever.

jimmy., July 2009

Probably caused by running under a low bush or similar, and bending the spring anchorage for the govenor spring. This is the movable lever that carries the operator control cable at one end, and the high speed govenor spring at the other. You need to bend it back into position so that when the operator control is at 'FAST', the engine operates at the correct speed.

phil_saunders(a)bigfoot.com

Phil Saunders, July 2009

Time to clean out the carb Chris - assuming the governor linkage hasn't been damaged or disturbed. The governor linkage works thus....with the engine switched off, the mower should be at full throttle or nearly so. When the engine starts, the throttle is moved automatically to the lower setting which is set by you via the throttle lever on the handlebars - but not all machines have this. If your carb sits in the fuel tank below it, you'll find that the dip pipes leading into the fuel reservoir have debris in them.

John, July 2009