lawn mower surging

[cpurvis]

One of the most interesting air filters is the oil bath. It requires intake air to make a very sharp 180 degree turn. The particles of dirt, etc., suspended in the air, being heavier, can't make as tight of a turn. The dirt goes straight while the air turns. A nearby pool of oil awaits, and they are trapped.

 

[motoman]

I remember the "ancient" auto oil bath filter. A solid packed ring of dirt would form in the bottom of the filter housing. But we still do not know how some particles find their way into the carburetor passage ways....A bunch of particles small enough to pass through the filter and then coagulate into blockages? Or is it always "gumming" via chemical reaction of different materials such as platings, rubbers, plastics, gas additives? Or both, and what is in StaBil and other additives that minimizes problems?

 

[reynoldston]

Dirty air filter plugs in which makes for a richer fuel mixture, which in turns helps do away with the engine surging. The OP has a engine surge so I would think we are going into the wrong direction here looking at air filters. Its been a long time age ago when I can remember a oil bath oil filter on a lawn mower. I am thinking like the old gas powered reel mowers back in the 40's and early 50's ???

 

[cpurvis]

I'm no expert on this but lawnmowers and the like operate in dirty environments (compared to the average car) and they usually have vented, unfiltered gas caps. That's one possible source of dirt. The small gas engine fuel filters I've seen look to be very coarse. Not sure how much good they do.

Ethanol gas doesn't help, eitherr. It draws moisture which causes corrosion as well as adversely affecting rubber items not designed for it.

 

[bigunn]

I quit using 87 octane years ago and that solved a lot of problems, I buy 10 gals of 91 at a time add 3oz of sea foam to each 5 gal. and I use this for all my 2cy to and my echo weed eater is 10 years old.