locating new carb for makita dcs520i; help please!

[thook]

howdy!!

as the title says, looking for a carb. but!! try finding one is the prob.

months ago, i cleaned the carb up after having some running issues; cutting out at idle and major trouble getting it restarted. i got it starting up better, but still cutting out. ran out of time to complete the job and shelved it until today. heck...now i can't keep it running long enough to tune.
there is a minor leak where the fuel line runs through the tank to the carb, but that part's new. so, not sure why it still leaks. happens when i refill, but not while actually running it. i'll fix it.
furthermore...and more to the point, my friend/neighbor suggested perhaps a new carb. says it's the original 25yr old carb, afterall. can't see why it really needs to be replaced..has a new kit in it and the seats don't appear to be damaged. i've never tweaked it hard enough to damage. ???
anyway, not opposed to a new carb...anything/everything to get it running as it should. i just can't seem to find one. friend believes there should atleast be something aftermarket, but i ain't seein' it. so, any help from you gentlemen would be lovely

-new ethanol free 89 octane
-proper 40:1 mix...synthetic
-new air filter
-new fuel line/filter
-great compression

thank you, kindly
~matthew

 

[Little Al]

According to the info I have the fitted carb is a Tillotson HU 116 A look on Tillotsons online pag WWW tillotson.ie should give info availability etc.

 

[Conquistador3]

Your carburetor most likely needs just a good clean and some new membranes.
The DCS-520 is closely related albeit not identical to the Dolmar 111 and 115 and all use various versions of the Tillotson HU family of carburetors. Kits for them are easily and cheaply available.
Even when the engine is stored by the rules, membranes go stiff over time, causing problems with fuel flow, causing all sorts of running, or no-running, issues.

 

[pioneerguy600]

One problem with cleaning and fitting up a new kit in a HU is there is a fine screen under a Welch plug in many of these carbs, they are often partially or wholly plugged up with debris , sometimes I have found the screen has been corroded by moisture and won`t let fuel through correctly.

 

[thook]

According to the info I have the fitted carb is a Tillotson HU 116 A look on Tillotsons online pag WWW tillotson.ie should give info availability etc.

thank you. i'll look them up!

 

[thook]

Your carburetor most likely needs just a good clean and some new membranes.
The DCS-520 is closely related albeit not identical to the Dolmar 111 and 115 and all use various versions of the Tillotson HU family of carburetors. Kits for them are easily and cheaply available.
Even when the engine is stored by the rules, membranes go stiff over time, causing problems with fuel flow, causing all sorts of running, or no-running, issues.

i cleaned it a few months ago. back in the summer...you know...when you're supposed to get your firewood cut...hehe. yeah, s'why i'm cutting now and having to borrow my friend's stihl

thank you. i have found/knew about the dolmar cross overs since i've had this saw. and, i have seen the kits all over the place. but, i put a new kit in a few years ago. and, i've store by the rules, but i wouldn't think a kit could go bad in just a few years time. ????

 

[thook]

One problem with cleaning and fitting up a new kit in a HU is there is a fine screen under a Welch plug in many of these carbs, they are often partially or wholly plugged up with debris , sometimes I have found the screen has been corroded by moisture and won`t let fuel through correctly.

i know the screen....and it's clean

 

[thook]

tillotson only has parts for the 116B listed. however, i can apparently contact them. that being said, there should nothing wrong with my original carb besides any of the soft bits and/or jets, right? i mean, those are the only that can "go bad", right?

like i said, the kit in it is only a few years old, and when i said i put a kit in it, i actually had a shop do it. so, wondering now if they put an entirely new kit in. though, it did run great after that. perhaps i should start by addressing the fuel leak....fuel line where it exits the tank. aside from yet another new line, is there something i can do to fix it? any fuel safe rtv's out there? is this leak even really an issue. my friend/neighbor explained it creates a loss of pressure the system needs to adequately create proper fuel suction by the engine. makes sense

 

[thook]

well, sharks....love it when i post questions on a forum and wind up answering them for myself...hehe

apparently, the minor fuel leak is not part of the running issue since the tank's already got a vent, anyway. still wanna fix that, though

and, apparently, yeah...the diaphragm can go bad in a few years time. makes sense. though, i use ethanol free fuel and store it right, i do usually only use it half the year. iow's, it sits a good while

so, that's where i'll start. pretty simple. rebuild the carb, again. oh, and get a new clutch assembly to stop the chain spin at idle. never been able to get rid of that for several years

 

[pioneerguy600]

The carb neither needs pressure or vacuum from the fuel tank to operate properly, actually it works best with just regular atmospheric pressure in the tank. The carb has a fuel pumping side to it and that creates a vacuum that draws fuel up into the carb so a small leak around a fuel delivery hose will not affect the carbs function . It may become a fire hazzard under the right conditions, many older saws I handled leaked fuel from vented fuel tank caps and we ran them anyway.

Ha , guess we were both posting at the same time.

 

[pioneerguy600]

I like these Sachs Dolmars and now Makitas, have a bunch of them here, mostly 115`s and a smattering of 110 `s, good saws for their time.

 

[thook]

re: posting......my notifications get delayed, so i'd no idea you posted...

i love my 520i. we got one brand new from lowes back in '94 or '95. it was such a big leap for my wife and i, at the time. i started cutting our own wood with a little mac, and after one winter of that decided i really needed ....well...something more to the task....haha. anyway, somehow managed to melt the cylinder and piston on that one after many years and refitted it with a used 520i we found on CL.....after i used that one long enough for body parts started going. plus, it didn't have the chain brake. needless to say, i don't see any reason to get a newer one until this one is simply no longer fixable. cuts everything i need it to......so long as it's running...lol. if i can ever manage to get the bar chain oil to stop leaking from the pump, i'd be even more pleased with it. tried many times with new parts and rtv. no luck

 

[pioneerguy600]

On this series of saws the oil most often leaks out of the oil tank around the pickup line, the OEM lines shrink a bit at the tank grommet connection. I have fixed many by removing the line, clean it thoroughly with brake cleaner or acetone, clean the hole where the line plugs into and when both parts are clean and dry apply some black Permatex to seal the oil hose grommet to the tank, let cure for a couple of days and fill with bar oil. Many of these saws are still in operation with no leaks since.

 

[thook]

well, i've tried rtv, but maybe i just didn't let it cure long enough. gave it overnight thinking that should do it. and, yeah...it's at the pick up line/tank where it leaks... though the line is new. nevertheless, since i'm gonna have this bugger all apart, again, to do the carb, again, i'll give the rtv another go with a couple day cure time.

gotta love a new chain! i've got my friend's ms290 on loan and the chain had been so filed down it wouldn't cut hardly through anything. new chain from lowe's and down came the 20 incher red oak this evening! made the ground shake...lol! top half is ready to burn, but the bottom/trunk i'll have to split and let it cure for next season. well, could be ready by february if i keep it dry. we'll see

 

[pioneerguy600]

RTV should work but both parts/sides have to be totally clean of any oil, let it set at least 24 hrs and should be a good long lasting fix.
An old chain can outcut a new one once its filed by the right person, there is a whole lot of background experience required though to make it cut better than new chain. Actually race chains are just about on the last filing or two of a chain`s life.

 

[thook]

i cleaned the orifice with brake cleaner before applying rtv and installing the new line. i even sanded off the flaking case paint upon "someone's" suggestion. maybe that's part of the issue....having changed the fitment by doing so.

i like to think i'm pretty good with a file, but as far as being the "right person" for race chain filing, probably not...lol! i'll have to look into that, though. i've got several chains it'd be nice to get a little more use out of. (referring to the 3/8 chains for my makita.) friend's ms290 uses a .325. if i can get the .325 filed "right", my friend can use it as a back up if/when his new chain....that i acquired.....gets a ding or simply wears. same goes for my 3/8's....for me, of course...hehe

 

[pioneerguy600]

You can have the cutters/teeth sharp as can be done and a chain will not cut, there is a balance that needs to be reached and kept between the cutters and the depth gauges. Many on here call it a progressive ratio or depth between the cutters and the depth gauges. The shape of the cutter, cleanout of the gullet and proper depth gauge height will contribute greatly to a good self feeding fast cutting chain. When a chain has the correct balance for a powerheads power band RPM the saw becomes a pleasure to run.

 

[thook]

hmmm. i do keep the depth gauges filed according to the cutter height. and, i try to keep a nice "bucket" shape to the gullet. my depth gauge tool may not be ideal, though. one of those standard box store things i got long ago. an oregon unit, i do believe. i've misplaced it since i last used it, so a good excuse to get a new one, i say. any recommends on that?

my 520i is all stock tuning as is friend's 290. will that make any difference? iow's, being stock, should i blow off the idea of "race chain" filing? not about to go modding anything and open up a can o' worms i'm not prepared to deal with. particularly this time of year

 

[pioneerguy600]

The progressive method calls for the depth gauges to be lowered much more than a standard gauge tool allows. There are many types of gauges on the market. The Carleton File O plate was one of the first progressive gauges, many makers have them out now. As the cutter is filed back the ratio between the top of the tooth and the depth gauge needs to be kept in the correct plane so the tooth takes the proper bite. I am an old hand filer, each of my saws runs a slightly differently filed chain, set to fit the power of each saw and for the type of wood I am cutting, cutter angles, tooth shape and depth gauge all set for that particular days cutting, different seasons also come into play as frozen wood cuts differently than wet /green non frozen wood.
Race chain would take years to get near perfect, actually never gets perfect as its an ever changing art.

 

[thook]

wowzer! my needs are much simpler than all that...lol! one saw for every application. and, when i asked about a gauge, i suppose i really just need a standard one, for now, to keep my standard filed chain/s in order. i never liked the oregon tool because it didn't have the flattest of file guide surface. looked like it was cheaply made....like something you'd get at harbor freight, maybe. looks like a gauge, but doesn't work like a gauge should.

as for the progressive method and gauge, will look into that , but maybe later down the road. heck....i just learned i should actually use a smaller file to sharpen once the cutter gets past the halfway point. another thing to research!

meh....time for more learning, eh...haha

for example, just learned...on this site....gullet cleaning generally refers to square chisel chains. mine is round. merrrgh!