air filter for 2 cycle engines

[Donald]

How important is the air filter for a 2 cycle engine anyway. The engine is always lubricated with virgin oil, no dirt in it. I know people say all the dirt your air filter misses ends up in your oil. But that in 4 cycle engines. My old chain saw has a decent air filter and it would rarely see dust, more likely small chunks that would be easy to filter with a window screen. I have seen some backpack blowers where you would expect a lot of dust have chincy oiled foam air filters that were not held in well and easily fell out. I have even seen some 4 cycle (Troy-Built) backpack blowers with the same chincy oiled foam air filter. Actually I should say I have see some Troy-Built without the air filter as it fell off and no one noticed. This certainly is only a little theory and not based on any fact. Just observation. The reason I got thinking on this topic is I saw a used Fradan backpack blower for sale. It had a 2 stage air filter which I never have seen on a 2 cycle machine.

 

[Chris142]

Very important! Before the fuel and oil get burned it lubricates the crankshaft and rod. Any dirt will grind away at the bearings then on to the rings.

 

[Donald]

Originally Posted By: Chris142

Very important! Before the fuel and oil get burned it lubricates the crankshaft and rod. Any dirt will grind away at the bearings then on to the rings.

And how would dirt getting past an air filter get into that fuel and air?

 

[Chris142]

Sucked through the carb.The oil and fuel mix does not go straight to the piston.It goes to the area where the crank is then up the side of the cylinder through holes then. It gets sucked into the combustion chamber.

 

[Chris142]

http://www.animatedengines.com/twostroke.shtml

 

[engineerscott]

Originally Posted By: Donald

Originally Posted By: Chris142

Very important! Before the fuel and oil get burned it lubricates the crankshaft and rod. Any dirt will grind away at the bearings then on to the rings.

And how would dirt getting past an air filter get into that fuel and air?

As long as you have a decent quality air filter .... it wouldn't. If not .......

 

[tdi-rick]

Plenty of saws get 'dusted', ask any shop that handles a large quantity of equipment. and FWIW most air filters on OPE are pretty poor, which is why heavy duty, usually two stage filters are offered on pro saws for dusty areas or dusty types of timber. (eg South Africa or parts of Australia which have totally different timber and conditions to, say, wetter areas like Scandinavia or the PNW)