Walk behind snowblower query

JDgreen227 · May 18, 2014

I am in the process of refurbishing a 1990 vintage Bolens 5 hp 4 stroke single stage blower, and the original carb heater box is aluminum and badly cracked from vibration. Can anyone tell me just how important a carb heater box is on a machine like this? I'm unsure if the temperatures during mid-Michigan winters are cold enough to actually require one. Thanks for any information.

oldnslo · May 19, 2014

Was this pre-heater box for covering the carb to keep the linkage from icing up or actually running warm air into the carb? On my older Ariens I have the linkage ice up on my blower a couple of times and only one had the carb ice up internally so it wouldn't run. Shut it of for a couple minutes and the engine heat thawed it back out. Mine has the sheet metal cover over the intake. Not sure if this is supposed to help direct warmer air into the carb or just reduce the amount of snow that gets drawn in.

JDgreen227 · May 19, 2014

oldnslo said:
Was this pre-heater box for covering the carb to keep the linkage from icing up or actually running warm air into the carb? On my older Ariens I have the linkage ice up on my blower a couple of times and only one had the carb ice up internally so it wouldn't run. Shut it of for a couple minutes and the engine heat thawed it back out. Mine has the sheet metal cover over the intake. Not sure if this is supposed to help direct warmer air into the carb or just reduce the amount of snow that gets drawn in.

Thanks for the input....the engine is a small frame vertical shaft Tecumseh and the carb is on the rear of the engine, facing the side of the operator. The aluminum box covers the entire carb and the air intake...but is open on the back and then there is a plastic shroud that covers the carb and air box...I have never seen an air box on a two stroke snowblower nor had one of those ice up...I really think it is there to provide warmer air to the carb on a four stroke engine.

oldnslo · May 19, 2014

I suspect you are correct, it provides warmer air for the carb and probably helps prevent the governor linkage from icing up.

JDgreen227 · May 19, 2014

oldnslo said:
I suspect you are correct, it provides warmer air for the carb and probably helps prevent the governor linkage from icing up.

Thanks for the input...I will repair the box with aluminum rivets and reinstall it...

pmhowe · Jun 16, 2014

I have an old Troy-Built snowblower. Last winter, it was acting up and I had to adjust the carburetor. I removed the metal box and tuned the carb. I left the box off so I could make adjustments if necessary next snowstorm. The snowblower ran fine the next time I used it. However, snow tended to get blown into the carb if the box is not there. Once I was satisfied the carburetor was properly adjusted, I put the box back on. I live at 8000' in Colorado. The temperatures when I made the adjustments were about 15 F below zero. The snow was very powdery. I think the box is to protect from snow. It may provide some residual heating, but I don't believe that is its main function.