From what I understand, all Lawn Boy engines are pretty reliable. We had one in the early '90s. It was a pre-Duraforce engine (4 or 4.5 hp, can't quite remember). I didn't care for the offset wheel deck or the 2-stroke engine design, but I'll say it was very reliable.
In general, dirt in a 2-stroke engine isn't good...moreso in them than in 4-strokes. For sure, you don't want dirt in ANY internal combustion engine, but with a 2-stroke engine, that air/fuel mixture enters the engine right in the crankcase, where the crank bearings and journal are/is. (Then it travels up above the piston, through a transfer port, to be ignited.) It's for this reason that I understand a 2-stroke is especially prone to dirt damage. It's bad enough for dirt to get by the filter on a 4-stroke, and potentially score the wall or mess up a valve, but the A/F mixture never reaches the crank area (except for any blowby). The 2-stoke has this added "vulnerability", and that's probably why they say to be careful with the air filter, and make sure it's sealing correctly.
I haven't heard of any specific issues with poor sealing. I have heard (but not experienced) that the OE Honda filter on the GCV160/190 engines don't seal well, and that an aftermarket replacement filter will seal better. I haven't had problems with my OE filter, so I can't say for sure. Perhaps a third party filter for the Duraforce would alleviate the poor seal issue, if there is one?
As an aside, is there a way to add a foam layer to the Lawn Boy filter box, to make it a "2 stage" filter? My Honda GXV140 commerical engine has that -- a foam "pre filter" and then a conventional paper pleated filter with rubber or urethane foam gasket material.
I hadn't heard anything about that before and was wondering if it were true and if anyone had any experiance with it and how to prevent it.
