OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Chainsaws and Concrete Cutters Petrol Chainsaws and Concrete Cutters Husqvarna 235

Hi people, I have a little husky 235 which is giving me trouble. Hard to start and no matter what I do it wont stop flooding. Wondering if some-one can give me a few ideas or the correct setting for the following carby. It is a ZAMA C1T, idling screw how many turns out, and also the high and low screws , and what would you use as it looks as if you need a special tool for it. Have gone right over carby and found no faults so I am hoping it might be the settings.

If you are sure it is flooding, that is unlikely to have anything to do with the mixture screws. Here is Zama's trouble-shooting guide:


As a starting-point for mixture adjustment, I've seen the following settings recommended on the internet:

High speed 5/8 of a turn from fully clockwise.
Low speed 1 1/4 turns from fully clockwise.
However, always begin by finding out how it is set to begin with, before you adjust anything. Note where the screw slot is pointing, then turn it gently clockwise until you feel it lightly touch its stop. Note how far you have turned it. Then put it right back where you found it.

The idle speed screw is simply adjusted so that the chain does not quite move when the saw is idling.

Hi Grumpy, thanks for that, just one little problem, the screws on the carby aren't really screws. It looks like you need a special tool to fit over them as there are no slots for you to use a screwdriver and I wont be able to get pointy nose pliers in. Is this a carby that cannot be adjusted. ( have tried putting up a photo, but not working for some reason )

Nearly all modern carburetors have tamper-proof mixture adjustments. Many have plastic covers on the heads of the mixture screws. Some others have screws with a "security" recess, so you need a special tool to adjust them. We need to see pictures to be able to tell which you have. More importantly, what makes you think it is a mixture adjustment problem, rather than a malfunction? Has someone previously been tampering with the mixture screws? Most owners make things worse, not better, by changing their adjustment.

You can see an image of a standard Husqvarna carburetor adjusting tool here:
http://ecx.images-amazon.com/images/I/71Hy-55HlPL._SL1500_.jpg

Hi Grumpy, sorry about the wait. To answer your questions, yes that is the tool needed to adjust the high/low screws. What makes me think it could a mixture problem is that having a good look around these screws there are some scratches on carby casing as well as the screws themselves. It seems as if someone has forced something in and tried to turn the screws. I used a pair of doctors locking jaw scissors and counted how many turns till fully in, 3.5 on low and a bit over 2 on high. Brought them out to what you have recommended, is firing with choke on but not starting, were as if you hold the throttle fully on it will start but dies as soon as you let off. Is getting fuel and good spark. (think I need to play with the idling screw bit more). When I had carby apart took a good look at diaphragm, needle etc, it all looked good. Have I forgotten something as it feels like I'm going backwards.

I think we have moved forward, Paul. Those settings seem to be telling us that the idle system has been blocked for quite a while, and someone has tried to compensate by opening up the screws. I suggest you begin by verifying the model number. Do this before you physically attack the carburetor. Here is where the numbers are located:



You have said that the type number is C1T, but let's be sure about that before we pick up the oxy torch.

The next step is reading the overhaul manual, which you can download (free) here:

http://www.lawnmowerpros.com/Shop/Zama/TechguideCC.pdf

You need to go through the overhaul procedure, as laid out in detail in that manual, for your model carburetor (probably C1). Note that from the symptoms, including the Stillson marks on the screws, you probably have a clogged idle port and channel, but we can hope that the obstruction will blow out with a strong blast or two from the carburetor cleaner can, using the long tube (supplied with the can) attached to the nozzle. Do not remove the Welch plug unless this process fails - see page 3 of the manual.

You may find you need to install a rebuild kit, when you get into the details shown in the manual. (You certainly will if you have to remove the Welch plug, of course.) Also, when you come to adjusting the mixture screws, you might try a trick others sometimes seem to use, with moderate success. Find a piece of thermoplastic tubing with an ID about the same as the root diameter of the splines on the screws, heat it up, push it over one of the screws, and let it cool. Then you hopefully will have a tool for making the adjustments. Depending on the quality and wall thickness of the plastic tubing, it may last for years, or it may die during this current project, but you can always cut off the last quarter inch of tubing, heat it up again, and proceed from there.

Hi Grumpy, thanks for the manual. To start off I cannot find any numbers on the carby what so ever except for Zama C1T, it does have different numbers on each arm,choke arm throttle arm etc, it is simialar to the top left one with the blue choke arm except my carby has a seperate primer, not attached as in photo. I was able to use the manual as a guide which worked a treat, never even thought about taking the mixture screws out. The idea of a peice of hose was wonderful, worked beautifully on the third peice of hose. Found out the low speed screw had a bit of gunk sitting in behind it, looked like a peice of sand but softer, I'm thinking sale dried out fuel as the chainsaw was sitting for some time. Blew it out backwards a couple of times just to be sure, then through were the screw goes and hey presto nice and free.Followed manual through to the end, put it back on chainsaw second pull it kicked over, just had to adjust the idling screw which I had to turn back off about three turns, now its running like a new one. Thanks heaps for your help and patience again Grumpy, its much appreciated.

Thanks for reporting back, Paul - it makes this thread useful to others, in the archives. Diaphragm carburetors are a bit weird and fiddly until you get used to them, and even then, it is really irritating if the metering lever spring decides to leap across the room suddenly, and hide. I'm certainly no expert - I often have to go through the rebuild process twice before I'm happy with the way the engine runs - but I'd say you were lucky to get such a good outcome on the first try. Reading and believing the manual is the key to success, though.

I'll close this thread.