tuning a saw?

[spudulike]

feeling the special love!

 

 

 

took carb to bits, all looks good welch plugs look snug as ought but expect i can't tell with the aye. put it all back together saw def still runs with L right in.

 

so cheap chinese carb time? £35 quid delivered

 

or NEW stihl one £113 inc vat with L and S

 

or i fix it some how? feels like a carb kit ain't going to change much as diaphram looks good etc? or i send it to someone for fixing?

 

as ever, thanking you

 

You will not see a leaking welch plug, do yourself a favour, take the carb off, if you have solvent in a can, carb cleaner, brake ceaner non oil based, take the L screw out, blast a little in there and also on top of the plug.

 

Leave to dry, get some superglue and work a little around the welch plug with a thin blunt instrument - tweezer ends, blunt small screw driver etc. Clean off the excess and leave to dry for a few hours or better still, overnight. really push down around the plug - dont go through it but don't ponce around:lol:

 

Try it again and the L screw, fully screwed in should kill the idle - as I said, the saw I had in recently did what yours is doing and I tracedit back to a leaking welch plug - it was a 365 with a Zama carb - the oval plugs tend to leak!

 

You could try another carb if you know of someone with one of these saws.

[josedelvecchio]

You will not see a leaking welch plug, do yourself a favour, take the carb off, if you have solvent in a can, carb cleaner, brake ceaner non oil based, take the L screw out, blast a little in there and also on top of the plug.

 

Leave to dry, get some superglue and work a little around the welch plug with a thin blunt instrument - tweezer ends, blunt small screw driver etc. Clean off the excess and leave to dry for a few hours or better still, overnight. really push down around the plug - dont go through it but don't ponce around:lol:

 

Try it again and the L screw, fully screwed in should kill the idle - as I said, the saw I had in recently did what yours is doing and I tracedit back to a leaking welch plug - it was a 365 with a Zama carb - the oval plugs tend to leak!

 

You could try another carb if you know of someone with one of these saws.

 

Hello buddies.

 

I think it has wrong iddle screw tuning. A too opened butterfly causes fuel to be taken almost completely from High speed circuit, so a change in L screw won't cause major effects...

[billpierce]

Hello buddies.

 

I think it has wrong iddle screw tuning. A too opened butterfly causes fuel to be taken almost completely from High speed circuit, so a change in L screw won't cause major effects...

 

well, just tried the idle (again!). so with L 1 turn out and H 1 turn out, i moved the idle all the way out then slowly put it in the saw would only run with it 3/4 of the way in and then the revs didn't pick up as it approached as far as it should go.

 

Spud, i tried the super glue, and working on the plug, also give it a good clean with brake cleaner. sadly its much the same......

 

so is it new carb time or soldier on with this one? full carb kit with needle etc? to me its starting to feel like new carb time, i can't see how the problem could be to do with anything else? aaaaaaaaahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.

 

 

these chinese carbs a joke?i can get 3.5 for the price of one walbro one!

[spudulike]

One thing I have found on some saws that have been messes around with - the idle screw is turned well in and the L screw is well out of position so would personally take the limiters off and turn the screws all the way in then both out one turn and then lower the idle until the idle is around right and then re adjust the L screw to make sure it is OK.

 

That Jose fella is making the point I was getting to in non technical terms as above. If the idle speed is too high, the L screw will do bugger all as the H speed check valve will be in action - so..........set the carb on one turn and one turn, start the machine and see what the idle does, if it is in act too high, lower the idle speed using the LA (idle) screw.

 

Once the idle is around 2700 rpm, you should be able to adjust the L screw correctly.

 

Try it - the Chinese carbs may be worth a go but don't expect too much!

[billpierce]

tried that i'm afraid, 1 turn out on H and L and started trying the idle from way out to about 1/2-3/4 of the way is in where the saw will actually tick over, won't go above 2200-2400 where ever the L or idle is. the only thing that makes the revs pick up is if you take the L screw way out so it becomes loose in the hole and air gets in like that.

 

I've just boiled the carb for 30mins (old fella at husky dealer said it might work?) but i'm not hopefull.

 

reckon it'll be a new carb mind you. feels like i'm giving in!

 

again, thanks for time and help

[wyk]

Did you say the butterfly wouldn't fully close?

[billpierce]

Did you say the butterfly wouldn't fully close?

 

nah, right at the start of trying to tune my 361 i noticed the throttle wire was a bit bend - only letting the butterfly open 45degrees as opposed to 90. it was closing up snug. sorted this out but hasn't solved the problem. but obviously confused the tuning a bit

 

just put it allback together to see if over night those wee elves come out and fettle it for me

[spudulike]

nah, right at the start of trying to tune my 361 i noticed the throttle wire was a bit bend - only letting the butterfly open 45degrees as opposed to 90. it was closing up snug. sorted this out but hasn't solved the problem. but obviously confused the tuning a bit

 

just put it allback together to see if over night those wee elves come out and fettle it for me

 

With the carb off and looking down the bore of the carb against a light source, how much gap is around the throttle plate and if you undo the idle screw, does it close completely?

 

You may have a severely worn L screw or seat that is letting fuel through when it shouldn't - in normal operation, the screw should cut the fuel off when wound in!

[billpierce]

when idle is out butterfly seals up real good apart from 2 tiny half moons which should be there anyway.

 

can i tell from looking if the L screw is over worn? can i get those screws bits seperately? is it worth further messing around/time/money? i'm pretty keen to get the bottom of this......

[billpierce]

Also from what i understand of what was said, the rpm limiter should be doing its wobbly thing to my tach around 13.5k? the tach reads up to about 9200 then reads 1700, this is obviously wierd and it occaisonally goes all over the shop but def settles on 1700 ish.

 

could that be some sort of fault or are these limiters pretty mental? with it tuned just over the 9200 mark it seems to cut ok, but it does cut out after medium- long cuts , which i can't seem to get rid of what with have little or no L adjust. also the idle is 2000-2400 rpm which doesn;t help - again i seem to have no control over this. sorry for repetition!