Husky 359 (carb?) problems

[popopboat]

My 359 almost wont four stroke,
Firstly it just wouldnt four stroke at all, even with needle valve almost all the way out.. an after 2-3 turns out it stops making difference.
Cleaned carb, replaced both diaphragm and membrane raised metering valve a bit, now it barely four strokes at full throttle.
needle valves do not make any significant difference, acceleration seems sluggish, im 99% that it doesnt leak on crankshaft seals(new oem seals)
Idle Needle doesnt make a difference until given throttle and i cannot really kill it by richening too much on idle valve.
Also it doesnt seem to be leaking air, can be easily killed with choke, just like perfectly working one.

Edit: rpm doesnt change a bit from rotating a saw in any direction

What do you guys think? Is it carb problem? I cannot really get new one in this time, so if its atleast temporary fixable it would be good.

 

[Bob Hedgecutter]

Have you ever taken the spark arrestor screen out and cleaned it?
The intake boot has the metal clip holding it to the cylinder and not a broken plastic one?
Bolts that hold the carb to the plastic intake block are not stripped?
Did you take out welch plugs and replace when cleaning?
Are ALL gaskets, plastic block and metering diaphragm in the correct order and position?
Did you replace the metering needle?

Did you start your rebuilt carb tuning by setting the low side first before playing with the high side? Sluggish acceleration is controlled by the low side.

 

[popopboat]

No spark arrestor, yep metal clip, bolts are holing strong, no replacements( nothing works here except markets with food and stuff), how tall should metering valve stand?
Yes i suppose they are correct order and position. Metering needle doesnt leak.
Nothing channels in carb seem to be blocked.

Yes i turn idle valve all way in and 1 1/2 turn back, H valve goes more turns out so it doesnt fall apart from rpm heh. (i start from far rich side)
Then i adjust them by sound, idle valve is usually there good, but i adjust H valve so it four strokes at no load at open throttle, but no in the cut.

 

[Huskitoter]

Guess you have checked the normal stuff, fuel line, filter, impulse line, vent?

Is it a zama or old walbro? It's easy to put the spacer in the wrong direction on the walbro.

 

[popopboat]

Unfortunately yes i did, zama carb.
I replaced impulse line with a bit longer one so it doesnt get bent and blocked.
It seems to run now well, but still needles do not make significant difference.

 

[Bob Hedgecutter]

The metering needle lever should sit flush with the top of the carb body- a ruler across the top of the carb main body should just brush/contact and no more the end of the lever that is held up by the spring and the diaphragm works on.
I can not get my head around what you call the idle screw- that does nothing but control the idle speed- the low mixture screw that controls the low speed circuit needs set properly before you go to the high mixture side.
Whilst we are all playing by the virus rules- video the saw running at low idle and then running at wide open throttle so we can see/hear the throttle response and perhaps judge more accurately.

 

[cuinrearview]

Is this the one you put the shims in the bearing pocket?

 

[popopboat]

Hi mate.
Same chainsaw, different case half heh.
Welli it was still holding well, it didnt move a bit and it way harder to remove with vise than the press fit.

 

[cuinrearview]

Hi mate.
Same chainsaw, different case half heh.
Welli it was still holding well, it didnt move a bit and it way harder to remove with vise than the press fit.

Glad you shored it up. You should go through the carb one more time including new diaphragms. Pull needles and spray cleaner through every oriface.

 

[popopboat]

Tank vent is just a hole in carb holder that vent pipe connects to, holds no pressure, should it be like that? On my other saw vent holds a bit of a pressure but not too much.

 

[popopboat]

Alright, i "fixed" it, nothing was apparently broken or bad, just a bit different than i learned doing.
Im used to have a full range od adjustment, from lean bogger to four stroking tractor, but zama doesnt allow that, only miniscule adjustments..
So i replaced main jet with one with a bigger holes, its working now and has full range of adjustment.
Thanks everyone who tried to help.

Forgot to mention, worn bar was cause for sluggish acceleration, chain was catching bottom of the rails on the tip of the bar and caused excess drag.
Now it accelerates pretty much instantly.