Dolmar PS-7900 Air Filter Question...

[Austin1]

Did you scare him with the Troll from Norway?

:biggrinbounce2:

Ya I did told him to not to mention the 290. Then I kinda trailed off with my 250 rant. Then told him about the Orange and Cream coloured husky think they call it a 361lol

 

[masiman]

Well, we're all terrified and we keep coming back

Moths to the flame.....:greenchainsaw:

 

[MCW]

I have to say I have had No trouble with the filter on my 7900 too the point I think I wasted money on a spare lol. I read this post last night Just got back from cutting some very dry pine mind you only ran two tanks through it but it is spotless. The out side of the saw is very dusty yes very sharp chain was making big chips but you still get lots of dust. The air box is even clean, dare I say Jred/Husky Clean.
I also did my good deed for the day by helping out another firewood cutter. Cutting on public land in the forestry on a Well Head road had another cutter pull up and say ah you got the good spot I told him tons of trees and the Dog would like some company as he had his Lab with him. He had a brand new MS 290 on it's Maiden Run. He forgot his Scrench and having a brand new truck no tools with him to adjust the new chain.So I lent him one of mine, after we cut are loads of wood he saw me pop of my top cover and have a look he asked what I was doing I told him so we had a Look at the Stihl and guess what No dust got by the filter either. Then I told him about AS, so next time we cross paths he will probably have a new MS460
P.S I told him don't get a fat ass 441 I also steered him to the Jred dealer too.

I've cut some dry Radiata Pine and also didn't notice any dust ingress through the filter either (although the wood dust is a similar colour to the housing so may be harder to see?). That was 3 or 4 tanks in a row I think. Where I've been really noticing it is after about 10+ tanks in a row through dead Australian hardwood. I was going to buy a spare filter too but might also buy the newer pre-filter housing while I'm at it.

 

[ciscoguy01]

Wood

Which is the case here. From the numbers I've seen, our hardwoods, (and it's pretty much all we have) and their densities make your hardwoods look soft.

http://www.arboristsite.com/showthread.php?t=73645

I do have the newer designed cover on my 7900, but I also cut with my 5100 and 510 also w/out a hitch. As for wood densities, below is a chart. In that chart, I've cut white oak, ash, locust, Hickory, Sugar(hard) Maple, Elm, Beech, Birch (both yellow and white). There's not much over there's thats much harder than these. I exclusively use Oregon LGX from the guys at The Cutting Edge on here. They put me onto it a couple years ago and I swear by it. Stays sharp a long time. The cutters are a blue hardened color. I've cut everything from Oak to Pine and Popple with that chain and haven't had a single issue, except I go through files a little faster.

For densities/btu:
http://forestry.about.com/cs/firewood/f/firewood_values.htm

For density per cu/ft lbs. :
http://forestry.about.com/od/firewood/a/firewood_chart.htm

You can also go to Sweep's:
http://www.chimneysweeponline.com/howood.htm

 

[SawTroll]

Ya I did told him to not to mention the 290. Then I kinda trailed off with my 250 rant. Then told him about the Orange and Cream coloured husky think they call it a 361lol

Cool!

 

[2000ssm6]

P.S I told him don't get a fat ass 441 I also steered him to the Jred dealer too.

You told him not to get the 441 but steered him to the jred dealer? Were you drunk, high, or just plain nuts?

Hopefully the man gets him a 460.

 

[SawTroll]

Quote:
Originally Posted by Austin1
P.S I told him don't get a fat ass 441 I also steered him to the Jred dealer too.

You told him not to get the 441 but steered him to the jred dealer? Were you drunk, high, or just plain nuts?

Hopefully the man gets him a 460.

Good man!

..Austin, that is.....

 

[MCW]

I know this thread is getting on a bit but tried something different today that actually worked. I had an aerosol can of Motoline Air Filter Oil 655 meant for dirt bikes. Gave the filter a spray of that (not too much - outside only). I then did about 6 hours of the filthiest, dustiest cutting I've ever done today in Aussie Hardwood with not ONE BIT of visible dust in the filter housing. The filter looked shocking on the outside after 6 hours but a bit of degreaser, some warm water, and a blast from the air compressor and it was looking brand new again. Despite the filter looking absolutely filthy the saw ran a treat and didn't lose power at all.
My 7900 is back in the good books again

Knowing my luck the degreaser will eat the filter over a few cleanings but seems to work at the moment!

 

[tdi-rick]

Cheers mate.
Was wondering about some filter oil but have been slashing, not cutting. :greenchainsaw:

 

[MCW]

Works a treat mate. Just read the can a bit more - its made by Motorex, Switzerland, but called Motoline - 750ml can cost $25.50 but will last me years. Didn't spray too much on in case it choked the saw.

 

[tdi-rick]

<snip>
In that chart, I've cut white oak, ash, locust, Hickory, Sugar(hard) Maple, Elm, Beech, Birch (both yellow and white). There's not much over there's thats much harder than these.

<snip>

Nearly all our common timbers are harder and denser than what is available in NA.
On the hardness front, black locust (7kN Janka) is softer than all the common eucalypts here, Hickory is getting close to a lot of common trees, (8.1kN) and yet is still only 1/2 as hard as the most common fire wood, fencing and construction timber, Iron bark. (had to cut up a few old strainer posts last week...)
Then we get into densities, Live Oak (the densest Oak I could find) is 945kg/m3 and Hickory is 785kg/m3. I'm pretty sure these figures are for seasoned timber.

Green, our hardwoods range from 670kg/m3 to over 1000kg/m3, and seasoned can range to well over 1200kg/m3.
Add in the inherent silica in a lot of areas and it's a pain in the arse.

Anyway, I've done what MCW did and sprayed my filters with filter oil, only I used Silkolene. It just happened to be on a shelf at the engineering supplies when I was picking up a new core bit.
Cheque book took a bit of a hammering yesterday when I went to town.
New core bit and adpater, can of oil filter oil, lift pump for the tractor, spare fuel pickup/filter for the saw and a new pair of chaps :greenchainsaw:

 

[MCW]

Anyway, I've done what MCW did and sprayed my filters with filter oil, only I used Silkolene.

I think you'll find it works a treat mate. My Dolmar will be getting another hammering this weekend in dead Red Gum/Eucalypts, although it will be a bit cleaner than where I was cutting last weekend.
Let me know how you go

Matt

 

[ciscoguy01]

Nearly all our common timbers are harder and denser than what is available in NA.
On the hardness front, black locust (7kN Janka) is softer than all the common eucalypts here, Hickory is getting close to a lot of common trees, (8.1kN) and yet is still only 1/2 as hard as the most common fire wood, fencing and construction timber, Iron bark. (had to cut up a few old strainer posts last week...)
Then we get into densities, Live Oak (the densest Oak I could find) is 945kg/m3 and Hickory is 785kg/m3. I'm pretty sure these figures are for seasoned timber.

Green, our hardwoods range from 670kg/m3 to over 1000kg/m3, and seasoned can range to well over 1200kg/m3.
Add in the inherent silica in a lot of areas and it's a pain in the arse.

:greenchainsaw:

:jawdrop:

I got nothing to say to that. Althoughhhhhhh, going from oaks and whatnot to the softer firs is alot of fun. It's like when your trying to make a grilled cheese on soft bread, ya know, when you use a stick of butter out of the fridge and then you grab the whipped margerine cause you've torn the bread up??? PITA... hehehehehehehe

 

[tdi-rick]

:jawdrop:

I got nothing to say to that. Althoughhhhhhh, going from oaks and whatnot to the softer firs is alot of fun. It's like when your trying to make a grilled cheese on soft bread, ya know, when you use a stick of butter out of the fridge and then you grab the whipped margerine cause you've torn the bread up??? PITA... hehehehehehehe

It's funny, I only twigged on the drive up to town (100km away) what black Locust was, bloody Robina Pseudoacacia.... (sound of hand slapping forehead) :monkey:
It's been introduced and is a friggin weed here, infesting creek and river banks...
We hate it as our horses have taken a liking to the leaves and it gives an adverse reaction

What we cut is also why no one here can believe the bars you fellas can get away with using there. :jawdrop:

 

[Termite]

"o" Ring

I was getting the same residue in my filters. I do not know if it will do any harm? However, I put a small "O" ring on the filter flange and that seems to have stopped the deposits. If anyone is interested I will take pictures when my wife returns from Florida with the camera!

 

[Andyshine77]

A pic would be nice.

 

[rbmopar]

Yes, I would like to see a picture of that too. I have been thinking about doing the same thing.

 

[JTElectric]

I haven't gotten a 7900 yet, but I also stuck an O-ring around the lip of the filter that fits inside the carb, (I'm assuming they're the same design?) and sprayed it with air filter oil, but I haven't gotten to cut with it yet. I was planning on it tonight but worked on my car instead.

 

[MCW]

My limited experience with my Dolmar suggests that most (if not all?) of the residues are coming through the filter element and not around it, hence the residue is inside the filter housing itself. A sniff of filter oil has solved the problem with no O-Rings involved - and that has been in some filthy, dirty, dusty Aussie hardwood too. There is definately some dust coming straight through the element in my case, no doubt about it.
I even gave the inside of the filter a sniff of oil just to see if any dust particles got stuck on the inside of the filter after passing through the oiled element - none did.

 

[Zodiac45]

My limited experience with my Dolmar suggests that most (if not all?) of the residues are coming through the filter element and not around it, hence the residue is inside the filter housing itself. A sniff of filter oil has solved the problem with no O-Rings involved - and that has been in some filthy, dirty, dusty Aussie hardwood too. There is definately some dust coming straight through the element in my case, no doubt about it.
I even gave the inside of the filter a sniff of oil just to see if any dust particles got stuck on the inside of the filter after passing through the oiled element - none did.

I think that the material is a product of very fine dust mixing with the oil in the fuel mix vapor. Cool that you found a "fix'. Glad too see that people are cleaning their filters out after every usage too. My own Dolmar 111 is very "particular" too the state of the filter. Gets boggy when it needs a cleaning.