This is what I do to the asians to keep the fines from passing around the air filter.
I thought basically
all saws suffer from this, but realize my only good OEM's are asian (Japan/Echo) but have seen fines-past-filters as a pretty ubiquitous problem...
Have been working towards eliminating them for some time now, and washers such as you show are IMO a requisite part of this, as is a hard-grease (I use 'lucas marine grease'/calcium polysulfide) to put around seals and, oftentimes, even around the washers added.
Huge fan of the specific type you show (#8 galvanized steel//rubber washers with a slight bend-inwards to the rubber side), but find they're best suited for air filters that have "some flex" like box-type paper filters (cs 590), whereas for hard/stiff/fixed-back filters like the 660 I prefer all-rubber washers (my vaporizing habit pays-off, I have virtually every thickness&diameter on-hand!) All-rubber gets the heavy grease as well, of course!
For my 590 the half/half washer works PERFECTLY, I have some grease on the other hole (and both of the rear mating areas) and zero fines get through it, that filter gets FILTHY have not yet remedied this (nor have I fixed/flowed the "carb spitback plate" inside that air filter, which isn't super restrictive like Lone Oak's below but can still be improved....but yeah pre-filtration on the 590 is garbage at least mine is, 1 session is enough to plug-up the filter badly, meanwhile I've yet to clean a 660 filter because of my pre-filtration (should also note that this design doesn't allow the hot flywheel air, and that I've closed-off that hole on the top-cover to keep my flywheel air exclusively on cylinder-cooling!)
I have been using Foam tape for the leaky filter fix. 2mm x 10mm
View attachment 312300
How did you get such great looking corners from a flat insulation tape?? I have the same tape in-hand right now and badly want to copy that (on
some units, others don't need it!) Such a pro/OEM looking job I wouldn't usually believe that was at-home work!! Badly want to copy that....have you been getting various
types / brands / makes of 660 filters? I ask because the biggest 2 differences I've found are:
1- Some have pleated perimeter, others are flat (pleated would of course flow better, all things the same!) and
2- Some do/do not have a rubber gasket, like you're applying to the carb-plate-wall, for instance:
The top one is a random generic, my only one that's pleated, and only one with a rubber gasket for mating to the carb-wall...
I left that high-porosity foam in the above picture as suggestion for you because am surprised to see you using stock carb-spitback-plate here, thing is sooo restrictive, didn't know it existed (MM's built unit didn't include one, presumably since it was built for short-term use) so was glad to learn of them sooner than later, but when I got my "Hyway high-flow" filter and found its inside had that bright green, high-porosity foam I thought WTH? Since, of course, porosity decreases with layers of filters, not increased
Then I realized
it's serving as the carb-spitback mechanism, you can see that dark area on mine where oil's collecting, once dirty-enough I'll wring it so the oil never reaches perimeter/my paper air-filter media, and voila no restriction and no spitback ruining flow of the actual paper-filter!
These aren't mine I'm doing this to. Customer's saws. They like the zero fines past the filter thing.
"Your customers"... sure
Heh I think we all hate/turn up noses at fines getting past, would expect so!! Have been fighting them for years now and pre-filtration is IMO a huge part of it, on my 660's I'm setting them up in a way that filters the (3) OEM air-inlets to the air-box, as well as a new large intake area that's also filtered, this allows more air with less fines....and lets me run the air-filter w/o those "wrap-around pre-filter socks" that come with a lot of filters (and must be choking-out air to some non-zero extent!!)
Do you use oil-soaked filters on all your units? I've been so interested in these* for a while now but too scared to make the change LOL...the thing is, Max Flo still has a limit on airflow because of that plastic cage, so for it to beat-out a paper filter that's got no cage supporting it, it would need to flow like 25% more or something (would need to do the maths) than the paper filters do...
One of the biggest things I'm hesitant about Re oiled filters is their consistency, it's like they don't offer consistent filtration, you set it up at "optimal" (since anything less allows fines), and - from there - it quickly plugs-up and loses porosity (far quicker than paper I would have to imagine), this has me questioning them for extended-use applications, eager to hear all you're willing to share on oil-soak filtration!! Also do you go for 60 or 80 porosity, as a rule? I hate the idea of "heavy duty" being used in-context of porosity, heavy duty should mean more pre-filtration, there's "optimal porosity" it's not like
more dust alters the max-size of particle we're OK with
//off-topic but to be clear it's proper/accurate to take my new spark plug and 'bend' the electrode, with my plug-gap disc, until it's at the factory-spec .5, right? Had been using out-of-box plugs, or the plugs that came in my units, and found they're not gapped remotely as wide as the OEM-spec for plug-gap
