Purchased a 2017 Dirty Hand Tools tow behind brush mower a few weeks ago and am sorting out all the problems. Previous owner had no clue, the swinging blades were beaten blunt, the mower spindle bearings were shot, some yahoo had installed the wrong sized drive belt, throttle cable was bent and partially seized.
I got all that dealt with, replaced the air, oil and fuel filters, fresh ethanol free gas, replaced the main 30 amp fuse so that the battery actually gets charged (at first the battery was being discharged by running the engine).
Engine (Courage 597cc 19 HP) is basically fine, no oil leaks, runs well. Installed an hour-meter/tachometer, at WOT it's running about 3200 rpm, idles at 1600.
Problem I can't get a handle on- after about 45-60 minutes of mowing it will start hesitating under load. By load I mean the mower is doing it's thing and you hear the engine speed drop like it wants to stall. It recovers when you stop moving, then starts bogging down again when I drive forward through uncut grass. The same type of field brush/grass that was not a problem 15 minutes earlier. The motor is so strong that you barely even notice a change in pitch when you get into the thick stuff and the governor adds throttle. Until it starts losing power that is...
Also when it starts doing this I noticed a stronger gas smell from the exhaust, like partially unburnt fuel is getting through- had one small backfire which made me suspicious. Which leads me to wonder about spark.
The only thing I have not yet replaced is the spark plug, because it seemed like spark is great. However I am wondering if a defective plug may seem to be fine but after an hour starts acting up. I just didn't recognize the symptoms as indicative of spark problems, nor taking that long to show up.
Any ideas?
Mark
I got all that dealt with, replaced the air, oil and fuel filters, fresh ethanol free gas, replaced the main 30 amp fuse so that the battery actually gets charged (at first the battery was being discharged by running the engine).
Engine (Courage 597cc 19 HP) is basically fine, no oil leaks, runs well. Installed an hour-meter/tachometer, at WOT it's running about 3200 rpm, idles at 1600.
Problem I can't get a handle on- after about 45-60 minutes of mowing it will start hesitating under load. By load I mean the mower is doing it's thing and you hear the engine speed drop like it wants to stall. It recovers when you stop moving, then starts bogging down again when I drive forward through uncut grass. The same type of field brush/grass that was not a problem 15 minutes earlier. The motor is so strong that you barely even notice a change in pitch when you get into the thick stuff and the governor adds throttle. Until it starts losing power that is...
Also when it starts doing this I noticed a stronger gas smell from the exhaust, like partially unburnt fuel is getting through- had one small backfire which made me suspicious. Which leads me to wonder about spark.
The only thing I have not yet replaced is the spark plug, because it seemed like spark is great. However I am wondering if a defective plug may seem to be fine but after an hour starts acting up. I just didn't recognize the symptoms as indicative of spark problems, nor taking that long to show up.
Any ideas?
Mark
