Woodplayer
ArboristSite Member
Well guys I had a strange problem with the 5100S I bought a little over a year ago.
It worked great last fall, This fall I had asked my dealer to order the metal ring insert which is intended to help with sealing problems between the carb and the boot as I checked mine and it didn't have one. A while later I had tried the saw with fresh 91 octane fuel and fresh stihl two strike oil (40:1) and it appeared to run lean at WOT in fact it would almost die right out. I decide to wait for the metal insert ring as I figured that may be the problem.
Well a couple months later still no metal insert ring at the dealer (he received only a couple and they went to other saws in the shop and no rings had been received since). I was getting impatient so I decided to order one from Cuttinscott who was able to send me one immediately (thanks Scott)
After installing the insert, there was no improvement in the operation. The saw will start and idle normally and accelerate quickly but after a few seconds of WOT, it seems to go lean in that it starts to rev faster for a second or two then drops off. (Similiar to running out of fuel) If I keep the throttle open it will often stall. If I baby the throttle the instant it begins to rev higher, I can keep it runnning at about 2/3rd top speed.
Things I tried:
Tried another plug (plug had very light brown colour,almost too light) the fuel mixture has been run in another of my saws so I am confident it is OK, I removed the plastic limiters on the mixture screws and adjusted the HS richer, checked the fuel filter (looked clean and could blow air through), air filter is clean checked the fuel hose for leaks/splits/cracks in the carb area as well as in the tank, put a tye wrap on the fuel line which connects to the carb as it didn't seem to be really tight, removed and reinstalled the carb a few times to ensure everything is mating properly and the mounting screws are tight, removed the top of the carb (metering area) and was able to blow through the high speed orifice with a rubber tube sealed over the hole with my mouth and there didn't seem to be any restrictions, the bar and chain is almost like new and lubed properly and rotates by hand very easily,
as well I tried loosening the chain etc., removed and cleaned the fuel tank air vent filter and I could blow through the vent by mouth with a rubber tube sealed over the vent hole, checked compression more than 180psi. I was stumped (no pum intended) To me it really seemed like a (lack of) fuel problem.
Now for the really odd part. As I was trying to cut a limb, I decided to cut from underneath, (using the top of the bar) and low and behold the problem went away. I immediately began cutting from the top (using the bottom of the bar) and the problem came back, as well when not even in the cut the problem persisted. Tried cutting underneath, problem went away for the duration of the cut.
I took the saw home, did some checks and found what I believe was the problem.
What do you think is my problem??????
It worked great last fall, This fall I had asked my dealer to order the metal ring insert which is intended to help with sealing problems between the carb and the boot as I checked mine and it didn't have one. A while later I had tried the saw with fresh 91 octane fuel and fresh stihl two strike oil (40:1) and it appeared to run lean at WOT in fact it would almost die right out. I decide to wait for the metal insert ring as I figured that may be the problem.
Well a couple months later still no metal insert ring at the dealer (he received only a couple and they went to other saws in the shop and no rings had been received since). I was getting impatient so I decided to order one from Cuttinscott who was able to send me one immediately (thanks Scott)
After installing the insert, there was no improvement in the operation. The saw will start and idle normally and accelerate quickly but after a few seconds of WOT, it seems to go lean in that it starts to rev faster for a second or two then drops off. (Similiar to running out of fuel) If I keep the throttle open it will often stall. If I baby the throttle the instant it begins to rev higher, I can keep it runnning at about 2/3rd top speed.
Things I tried:
Tried another plug (plug had very light brown colour,almost too light) the fuel mixture has been run in another of my saws so I am confident it is OK, I removed the plastic limiters on the mixture screws and adjusted the HS richer, checked the fuel filter (looked clean and could blow air through), air filter is clean checked the fuel hose for leaks/splits/cracks in the carb area as well as in the tank, put a tye wrap on the fuel line which connects to the carb as it didn't seem to be really tight, removed and reinstalled the carb a few times to ensure everything is mating properly and the mounting screws are tight, removed the top of the carb (metering area) and was able to blow through the high speed orifice with a rubber tube sealed over the hole with my mouth and there didn't seem to be any restrictions, the bar and chain is almost like new and lubed properly and rotates by hand very easily,
as well I tried loosening the chain etc., removed and cleaned the fuel tank air vent filter and I could blow through the vent by mouth with a rubber tube sealed over the vent hole, checked compression more than 180psi. I was stumped (no pum intended) To me it really seemed like a (lack of) fuel problem.
Now for the really odd part. As I was trying to cut a limb, I decided to cut from underneath, (using the top of the bar) and low and behold the problem went away. I immediately began cutting from the top (using the bottom of the bar) and the problem came back, as well when not even in the cut the problem persisted. Tried cutting underneath, problem went away for the duration of the cut.
I took the saw home, did some checks and found what I believe was the problem.
What do you think is my problem??????
eh?
