The H & L needle valves on my husqvarna 51 chainsw need to be out several turns to get it to run. it than runs fine until you try to cut with it and than it bogs down. Everything i have read indicated the needle valves only need to be turned out 1 or 2 turns. Problem?
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Several bar and chain combinations fit the 51 model saw. If your saw runs an H46 / H80 or H81 style chain you will need a 7/32" (5.5 mm)
If you are running a H21 style chain you will need 3/16" (4.8mm)
I have not seen a chain saw that must have the carb removed to remove the needle valves. The needles are nomally exposed so they can be adjusted while the saw is running. There are 2 of them.before you take them out turn them gently in till they stop counting the turns.. then pull them out and spray some carb cleaner on them and into the hole they came out of.one at a time because the tip of the needles may be differnt. then gently turn them all the way back in and turn them out the number of turns you counted.
Adjust the fuel and air mixture screws while the saw is running... you'll find that "sweet spot"... it just takes a little patience! Small adjustments... If you over adjust and the saw quits running or starting, GENTLY turn both screws in all the way (don't damage the needle valves or seats) and turn both out one and a quarter (1 1/4) turns out. The saw should start, then adjust from there.
start by checking all ur fuel lines for holes then proceed to clean or rebuild ur carb the ethonal in fuel is cloging small engine carb jets and making needles stick so then adjust ur carb back to factory settings try with new air filter as well and run 89octane or higher in your two stroke motors u will c a great differance in performance
Find the gas/air adjustment screws on the carb (next to the the throttle cam where the throttle cable attaches. Turn the screws in all the way... GENTLY... Those are needle valves, and too much torque on them will damage the needle valve seats. turn both of them out one and a quarter to one and a half turns. Start the saw, and adjust one or the other screw in or out until the saw runs properly. If there is a plastic stop installed on the screws, remove it first, and replace it after the saw is running properly. You have to be patient while tuning the carb as it may take a while. If you adjust too much and the saw refuses to start at all, start over with the 1-1/4 to 1-1/2 turns out on the screws.
As far as i remember Husqvarna never produced a model 178, however if adjusting the mixture screws does not help there is either a fuel blockage in the fuel filter in the tank ( replace filter ), or the fuel screen in the carb ( strip clean and service carb ), check the fuel hose hose for splits or cracks, asthis will greatly effect the running
Does it run O.K. with high revs. with no load, but dies when you start to cut (load) ? If that is the case your carb. needs to be adjusted and that is difficult to put into words. Without knowing what make of carb you have because they can change from year to year, and also depends on the model. Without knowing make of carb I suggest you try to turn the L (low) and H (high) needles in (clockwise) until they are lightly seated so you don't damage the needle or seat. Now turn them both out (counterclockwise) one turn as a start. Start your saw to let it warm up now rev it up it should not hesitate or run rough while reving up. If it does turn low needle out 1/4 turn or more if needed until it does not hesitate. (turning any needle out will let in more gas turning in less gas) If you get this far good idling and reving up, now adjust high needle the same way. With high needle you can also try turning it in. keep on adjusting needles in or out in small increments until it runs right. If you cannot get it running right after all this, you probably need a carb overhaul, just a cleaning or carb kit if diaphrams are stiff or damaged. I hope this helps you. Please forgive grammar errors. Let me know how you made out.
Turn both jet screws CW to stops (lightly), then back each out CCW 1-1/2 turns. This is a basic setting and should allow the engine to start and run. Start the engine and allow to warm up, then pull the throttle full on. Turn the H needle CW until the engine starts to speed up, but still 4-strokes. Correct adjustment is when the engine 4-strokes running free, but immediately 2-strokes when cutting. Release the throttle and adjust L needle so that the engine idles fairly well, but allows the engine to 'follow the throttle'. Adjust idle speed screw so that the chain stops turning, but the engine continues to run. Hope this helps!
I don't know if your saw has adjustable needles on the carb, but if it does, the "low" side needle needs to be turned counterclockwise about 1/8 to 1/4 turn. THis will richen up the idle mixture which will take care of the sputtering, and should also bring down the idle speed.