Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have an Ariens 7524E with a Briggs & Stratton engine that I used as recently as several days ago (Thursday) for about ½ hour to clear my driveway, without problems. This morning when I tried to use it on last night’s snowfall, I found that it stalls after moving snow for about 5-10 minutes.  It starts easily and runs fine up until the engine begins running erratically, and in about 10 seconds or so after that it stalls.  Once it stalls, the only way to restart it is by priming it once, but then after it starts it only runs a few seconds before stalling again.  Changing choke position doesn’t seem to make any difference in keeping  it running.   

I should note that after I place it in my garage (thermometer in there says 48 degrees) for about 40 minutes, it will start fine again and will move snow for another 5-10 minutes before stalling again.  As an experiment to see if the problem had anything to do with engine temperature, this afternoon I started it on a cold engine (it had sit in my garage for close to three hours since last use) and left it run at idle for 25 minutes until it got adequately hot, and all was well until I began moving snow with it – again, in about 5-10 minutes, the engine began stumbling and stalled.

This machine is less than a year old and probably has less than 4 hours of run time on the engine. I bought fresh gasoline from a busy gas station just before using it several days ago, and this same fuel was used when I cleared my driveway then. So I’m inclined to believe it’s not old or water-laden gasoline, otherwise I might have expected to see the same behavior a few days ago.  The fact that it’ll run at idle for 25 minutes without stalling also suggests to me that the problem is probably not related to the gasoline itself (if there were water or dirt in the fuel, would it not have stalled again?). I considered draining the fuel and buying fresh fuel someplace else to see if that makes any difference, but in my mind I’ve ruled out fuel as the problem because the same batch of gas was used successfully several days ago – am I using faulty logic here? Maybe it’s just a lucky coincidence that it idled fine for 25 minutes this time…..

I’m having the local Ariens dealer come to pick up the machine the day after tomorrow (with repeated snow events every few days, I need to get to a working solution quickly), but would like to try to determine if there’s anything else I might try on my own before having to spend $$ for the dealer to look at it. Do any of you experts in the audience have any suggestions or insights based on previous experience that may help diagnose this problem?

Snowmann, Thanks for your suggestion. I always secure the fuel cap tightly, so I'll try to close it a little less snugly this time (but not so loose that fuel spills out) to see if it relieves the problem. 

One new observation I had last night when taking another look for anything else out of order.... I always turn the fuel valve off before rolling the machine back into my garage, and of course I have to open it before starting the machine. When I opened it last night, I heard a kind of suction sound and then the gurgling of liquid for a few seconds, something which I've never heard before when opening that valve. Sounds like a vacuum forming that prevents fuel flow as you noted.  The question I'm pondering is, why doesn't the same thing occur when the engine idles for nearly a half-hour, but 5 or 10 minutes into blowing snow, it stalls.   I might speculate that this is consistent with water freezing in the cap breather and creating a vacuum which prevents fuel flow, which would explain why it resumes operating after sitting in a warm garage for awhile. Hmmm... maybe it works fine when idling outdoors for a half-hour because there's no snow drifting back over the engine and the fuel cap breather remains dry and clear, but when I start moving snow, anything that drifts back over the engine may be finding it's way into the breather and freezing there.    Does this sound like a reasonable explanation?

I'll definitely try running with the cap attached less snugly to see if it is an effective remedy.  Thanks for the tip!

Hmm... I guess my hypothesis isn't right.  I just looked at my gas cap (to see if any foreign matter appeared in the breather hole) expecting to see a small hole in the top of the cap, but there is none - it appears to be a solid, unvented cap. This is on a Briggs and Stratton Powerbuilt Snow Model 12000 engine. If there's no vent hole in the cap, what prevents a vacuum from building in the tank that prevents fuel flow... is there some sort of relief valve someplace I don't see? The owners manual says to "tighten the cap" after refueling, so it sounds like they're not relying upon an incomplete cap seal to permit fuel to flow. (Nevertheless, if this approach resolves my problem without creating a fire hazard from spilled fuel, I'll use it.)