Hello, I am new to the forum and would appreciate opinions from those more experienced than me on a Tecumseh HMSK100 that I'm trying to rehab. The engine is on a ~1973 Ariens two-stage Sno-Thro that I picked up for free over the summer. I don't know the maintenance history, or even if this engine is original to the machine, but I know that it is a John Deere badged Tecumseh HMSK100-159182T (D). The engine ran when I got it, but not well. It also had signs of neglect (very grimy/dirty, dirty oil, nearly dry auger gear case, etc.).
Since picking it up, I have installed a brand new carburetor and new spark plug, changed the motor oil and auger gear case oil, replaced the fuel lines and inline filter, and lubricated the throttle linkages. The motor runs decently now (no problems starting up using the electric starter, idles fine) but stumbles as the throttle is increased. I don't know if what I'm seeing is properly called a misfire, but as the throttle lever is increased the engine will almost die, the muffler will cough smoke, and then it will typically recover and get up to full throttle. If the throttle is increased too quickly, the engine can die when it hits the "stumbling" point. If the throttle is raised slowly, it usually recovers and gets to full throttle. I have been using it in this state to clear snow, it works well enough but does make me nervous that it's going to bog down and die in wetter snow (I'm not sure if this is a symptom of whatever is wrong with the engine or just a limitation of the power of this engine, this is the first snow blower of this type that I have owned).
While I've tried to describe the problem in some detail, nothing beats a movie, so I made one. Please see the YouTube link below (look for the stumbling at about the 0:14 and 0:48 second marks):
I have about gotten to the end of my experience with coaxing small engines back to life. I would appreciate any suggestions of where to look next to figure out exactly what is causing this problem and fix it. Thank you!
Since picking it up, I have installed a brand new carburetor and new spark plug, changed the motor oil and auger gear case oil, replaced the fuel lines and inline filter, and lubricated the throttle linkages. The motor runs decently now (no problems starting up using the electric starter, idles fine) but stumbles as the throttle is increased. I don't know if what I'm seeing is properly called a misfire, but as the throttle lever is increased the engine will almost die, the muffler will cough smoke, and then it will typically recover and get up to full throttle. If the throttle is increased too quickly, the engine can die when it hits the "stumbling" point. If the throttle is raised slowly, it usually recovers and gets to full throttle. I have been using it in this state to clear snow, it works well enough but does make me nervous that it's going to bog down and die in wetter snow (I'm not sure if this is a symptom of whatever is wrong with the engine or just a limitation of the power of this engine, this is the first snow blower of this type that I have owned).
While I've tried to describe the problem in some detail, nothing beats a movie, so I made one. Please see the YouTube link below (look for the stumbling at about the 0:14 and 0:48 second marks):
I have about gotten to the end of my experience with coaxing small engines back to life. I would appreciate any suggestions of where to look next to figure out exactly what is causing this problem and fix it. Thank you!