I have a Tecumseh riding mower 17.5hp OHV175.The engine races up and down when mowing.I have changed the fuel filter and the spark plug and have checked the carb.float and it is not stuck.Also I have changed the fuel.Thanks
It sounds to me like the tube going to the oil filter has a leak in it. you should check that. other than that the only thing that could cause the symptoms you have described is the air adjustment screw, on a tecumseh engine. try turning it in or out to see if that solves your problem.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix lawn mowers.