black soot coming from B&S (Sears) tractor engine

ramone899 · 09-16-2009, 11:30 AM

Hi all. Bought a new Sears lawn tractor last May, with a 21 hp B&S "platinum" engine, Engine and tractor running fine but recently I noticed a lot of fine black soot all over the engine compartment and underside of hood after each mowing. I've changed the oil (not the filter) once so far, otherwise the tractor is same as delivered. I'm running the engine for about 90 minutes each time I mow the lawn, not putting any unusual stress on it.

Does anyone know where the soot may be coming from, and if it is a sign of engine trouble?

thanks.

k2skier · 09-17-2009, 09:56 AM

My main concern is why it's all over the engine. Check the muffler deflector, it MUST be pointing outside the hood. Once the engine inhales exhaust fumes it becomes a compounding problem by choking off the air flow from plugging the air filter, change the air filters. Make sure you're using straight 30W oil only. It make have a leaky inlet needle in the carb making it run too rich.

09-16-2009, 11:30 AM	#1 (permalink)
ramone899 Registered User Join Date: Jun 2009 Posts: 8 OS: winXP	black soot coming from B&S (Sears) tractor engine Hi all. Bought a new Sears lawn tractor last May, with a 21 hp B&S "platinum" engine, Engine and tractor running fine but recently I noticed a lot of fine black soot all over the engine compartment and underside of hood after each mowing. I've changed the oil (not the filter) once so far, otherwise the tractor is same as delivered. I'm running the engine for about 90 minutes each time I mow the lawn, not putting any unusual stress on it. Does anyone know where the soot may be coming from, and if it is a sign of engine trouble? thanks.

09-17-2009, 09:56 AM	#2 (permalink)
k2skier Registered User Join Date: Sep 2008 Location: Oregon Posts: 313 OS: XP Home-SP3 My System	Re: black soot coming from B&S (Sears) tractor engine My main concern is why it's all over the engine. Check the muffler deflector, it MUST be pointing outside the hood. Once the engine inhales exhaust fumes it becomes a compounding problem by choking off the air flow from plugging the air filter, change the air filters. Make sure you're using straight 30W oil only. It make have a leaky inlet needle in the carb making it run too rich.