I can't get gas to the cylinder of my Stihl, FS81 trimmer. I have air, spark and the fuel line is clear from the pickup to the carb manifold. I'm pretty sure I have a clogged jet. How do I identify the carb model should I need a rebuild kit? It is a Walbro carb and has numbers on a variety of parts, like WT 45A H7. The trimmer is between 15 and 20 years old. I would also like to know how to determine it's age from the serial number.
Well I would go with fuel supply. But did you pull the hose off the carb inlet and see if fuel flows freely from it? You do have a filter screen inside the fuel tank on most makes and it can get plugged, if it is plugged blow compressed air back into the tank to clean it and then dump and flush the tank..
The culprit here is the vacuum leak at the cracked manifold, that much I am sure of. I would have replaced it or used a good industrial epoxy to fill the crack but not silicone, that is at best a temporary repair in my humble opinion, I don't like to "Jerry" rig things.
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SOURCE: stihl line trimmer starts but won't stay running
check to make sure your kill switch is not shorting and you have the right gap from the coil to the flywheel also if the flywheel sheer pin is damaged in the least this will cause a multitude of problems... it is the timing pin and must be in good shape not damaged or sheered ..any way reply to [email protected] and i will try to help you through this.... DALE good luck and will wait for reply..
SOURCE: I need the fuel line diagram for a Walbro carb. Wt 231 k1
need to know which feul and which is return
SOURCE: Can sombody say what model the carborator is for
On mine the # is on the bottom and looks like WT 685 or WT 68S.
SOURCE: String trimmer, fuel lines disintegrated, I need routing.
The Walbro has two connections on it for the fuel line. My Walbro has one connection on the side of the idle screw and main fuel adjusting screw. This connection hooks up to the suction side of the primer bulb. Usually the shorter stem. (You actually **** fuel through the carb instead of pushing it through.) On the other side of the carb is the other hook up. It draws fuel from the tank. This line will connect to the side of the tank that has the filter. The other side of the tank is your return and it hooks to the other connection on the primer bulb. Usually the longer stem.
SOURCE: Which fuel line "port/inlet" on the Walbro wt-380
Usually the line with the filter on it that comes from the tank goes to carb. inlet first which is most likely close to the bottom side of the carb.nearest to the engine,then the outlet or return line on the carb.goes to the inlet side of the primer and the outlet side of the primer goes back to the tank. The primer draws fuel through the carb to the primer to the tank if its not? then correct the line connections until it does
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I have squirted fuel into the cylinder via the spark plug opening and choke portal. In both cases, the trimmer started up immediately and ran until the fuel in the cylinder was used up. I now have a carb rebuild kit, new fuel line and filter. So we'll see if that fixes the problem.
Here is how it ended. I purchased a carb rebuild kit, fuel line and filter. I installed the new fuel line and filter; disassembled the carb, blow out all the ports and innstalled a new diaphragm only from the rebuild kit. I also filled a small crack in the plastic carb manifold with high temp gasket silicone (I thought the crack may have been breaking the vacuum).
I put everything back together and it started on the third pull. So honestly, I don't know which action or combination there of actually fixed the problem. But regardless, it's running like a champ now. One additional thing; the carb ID was in fact, WT 45A H7. However, according to the Stihl manuals, this carb should not be on this model trimmer. If I had not torn down the carb and gone strictly with Stihl's specs, I would have purchased the wrong rebuild kit.
I could not replace the manifold w/o buying a completely new carb. When we checked the schematic drawing for the carb, it didn't even show a manifold. So something tells me this trimmer was produced during an "engineering change" on the assembly line.
Also, the crack did not appear to propagate down to the elbow of the manifold. So I'm not sure there was ever a leak to begin with. I was simply taking a "belt and suspenders" approach to problem resolution. I agree, epoxy would have been better, but this is a 650 degree, gasket grade silicone, so I think it should hold. A new carb starts at around $80.
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