The problem with the Husqvarna 235 has nothing to do with the fuel tank vent, and has everything to do with the carburetor. Fuel bulb is called a purge bulb not a primer bulb. Purge bulb has only one use, it supposed to purge the air bubbles out of the carburetor and fuel lines. A primer bulb is used on lawnmowers, and pumps fuel directly int the venturi. If fuel is puddling up under the carburetor from pumping the purge bulb the carburetor has a defective check valve. You should be able to pump a purge bulb all day long and never leak one drop of fuel. Husqvarna would never admit that the zama C1T-W33c carburetor is a defective design and should of been recalled from day one. Actually the tank vent was designed to be under the carburetor for the reason of recycling any unspent fuel back into the fuel tank to meet EPA standards. Now most saws have a fuel line directly from the tank vent either back into the fuel tank or into carburetor air filter box. The best way to remedy the ongoing issues o bogging with the Husqvarna 235 would be to find an aftermarket carburetor and throw that Zama carburetor in the scrap bin where it belongs! I would bet that shortly after this video that the bogging issues surfaced again. I would really like to see an update to this fix to see how long it lasted. I refuse to work the Husqvarna 235 anymore, I always recommend to anyone that wants me to work on a 235 to cut your losses and scrap the saw and not try to sell it to someone and have the same issues.
I was watching a Vid by Donnie Walker, recently, and gave a Part # for a VENTED Gas Cap! #503-82-8005 for the Gray Cap and 8004 for the Green one!!!! But I had already started on trying to remove my Vent! D'OH!!!!! (My 235e doesn't have a Vented cap)
I need help ....I just bought an Husqvarna chainsaw 326 it started when the fellow tested it but the day after only enjoyed for fifteen minute then it become a night mare . (long story short ) I replaced the carburettor ---new one from China --- replaced it but stil didn't start and because it hard to pull the rope i decided to have a look the piston.... it shoes a little scratch on the front --muffler-- has not damaged the ring and the cylinder ...then I tested the ring in the cylinder for any major gap It does have a gup of about one millimetre is that ok or I have to replace the ring and the piston ? Thank you
My wheel gears wear on the edge was caused by the wheel mounting plate being toed in. This is how I fixed mine without having to replace the wheels. Because just the tip end of the wheel gear was worn it worked after I made the mounting plate parallel. Hope this helps. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-RVK_po7BRZs.html
This is the most nasty full of issues chainsaw from Husqvarna but I think the most important isue is the carburetor which is made by zamma China if you buy a new one original not aftermarket it will run better a period of time after that it will have the same problem.I think that the big problem is carburator.
Great video!!!, after seeing this I decided to take the top hose off the primer which connects to the tank next to the vent that you perfectly explained, and that solved the issue for me so far, I don't need the primer anyway, the choke is good enough. So I'm using the primer hose now as a vent.
Thank you!!!!!! Rebuilt engine - repaired cracked engine case by head that all these engines have, and it surged. Now this vid is exactly what was wrong....torn gasket, My thanks
Great video, was also having a problem with an SV601 3212. Carb no longer available. Got a chineesium, put on, still surges 😢 So I tried your solution, and was excited when I found a hole in the gasket. Installed new gasket, and... whallah! It DIDN'T help 😢 Tried the hidden screw thing, STILL surged. This mower I'm working on was previously touched by someone that couldn't spell "gas" if you gave him G&A. Things broken, missing, loose, etc. Nightmare. Anyway, I decided to try re setting the governor, and that was what it was. Great video though, appreciate you sharing your experiences, and maybe my experience will help someone eventually
Great video 😊This is a big problem! I don't know why Husqvarna have not shared information about tank/vent/pressure requirements ??? I have done everything to Mt 562xp auto-tune and it still won't go.... prob wasted money on a new carb as I first thougt that was my prob inspected that vent, cleaned it, broke it, bought and waited for a useless defective clone product. Have endlessly searched for a legit on. Made my own even... but i😊 still have no idea what the f*** I'm doing it still won't turn up properly if I manage to start it
When I throttle up my SV470 engine until that little cutout in the throttle lever where max power would be, my engine surges badly, almost to the point of shutting off. I have to lower the throttle back down about 1/4 inch below that little cutout to keep the engine at full speed, I may have to check on this gasket on mine. Thanks for the video!
The air vent should be in the cap gas tank because the location of that air vent shall accumulate the residue of the fuel oil and the wood powder, then it will be easy to maintain. I have that problem I searched a lot to find the location of that air vent I couldn't find it except with you. (Thanks for sharing) I realised that was the problem because when my chainsaw stopped and when I opened the cap the air was suced in, so in conclusion, it is better when starting to turn it on to not pump a lot of fuel so it will not exceed the carb out and then it will be reabsorbed with the wood powder.
Op can you share the other videos you referenced? I have the exact same sv540 kohler courage which has a slightly different carb and setup than the larger models..which is all im finding videos for
Honestly I don’t remember any of the other videos. It has been a long time since I worked on this mower and figured out the fix for my specific engine. Sorry! I would just search “kohler surging” and keep going through the videos that have engines similar to sv540.
hey great vid hate to say it , i had this same problem, same machine. also did Darrells gasket trick previously (late to the party ) 😂 had the serge , new gasket. 😃done thx👍
Does anybody have a pic or video of how the linkage rods from carburetor connect to the control levers/mechanism? This would be where the rods connect to controls where throttle cable is connected. Thx
This is exactly what I'm looking for also, my 18hp courage is exactly like this, but the engine is on low idle while the lever is at full throttle. Need to find where to make an adjustment before putting hands on it and making it worse.
Man its 330 am im still trying to get my Fuel live from the right of the Tank Nd i got everything hooked but having difficulty getting the fuel line that gose fro the tabk yo the Bubble!
Man great video. I have one of these saws in my shop. Will try to start, but will not idle. When I pull the trigger, it tries to run but bogs down and stops. I drained fuel, saw that the fuel filter was broken off the end of the fuel line inside the tank, and the fuel line was yellowed and brittle so I ordered the oem from Husqvarna and changed. Checked carb diaphragms and they are still flexible so I put back together and same result. I’m wondering if I have the same issue. The saw will start, but will not idle and will only run if I give gas on the trigger, which sounds like fuel starts to get through but then a vacuum gets created due to blocked vent. I do have one question for you, when you replaced the tank fuel line, where did you get it from? I may have missed it in the video. Thanks again!
My fuel line was dry rotted, the filter fell off, and within just one use of it off, it literally clogged the screen chock full of debris. There is a very fine screen under the diaphragm plate where the fuel line goes in. I messed with the carb the same way you did, and it would be fine one minute and bogging the next, check the screen it's easier than it looks. it's been a great saw ever since.
Any air intake leak can cause surging. You might want to consider keeping the intake area cleaner than what you shown in the video. Even a micro piece of dirt that gets inside a carb orifice can cause trouble.
Brilliant bit of troubleshooting, but this could have been a 5 minute video if you’d planned what you were going to say in advance. This wasn’t a murder mystery, no need to drag it out!
I needed the heat deflector gasket like that at the time I didn’t have one I made one out of card board till I got mine in the mail but it worked great!
Great video, and a big help, Thanks. it covers a subject that does not have much presence online. A blocked vent / duckbill creates vacuum in the fuel tank , when using a vacuum pump for diagnosis I do believe that the vent is supposed to be only a small leak , only lets enough air in to replace the space created when fuel is used and yet keep gas fumes in the tank. So the testing pump will still be able to create a vacuum but will leak down slowly. Mine was plugged on a new saw, neothec husky 365 clone. The screen had what looked like orange paint overspray on it. When the saw was hot and shut off I could hear a slight "whistle" the air getting sucked in through the screen believe it or not.