Chainsaw problems

[Argonaut]

I have a McCulloch 360T
Starts fine .. either hot or cold ... which in itself is a good indicator that many things are Ok with the saw.

In use ... be cutting fine then revs will die, then get to a point with chain out of the wood .... tickover is fine, but when I try to rev it picks up, but after about 20-30% of power then dies off ... often to a stall. Can't get it up to speed.
It can often take 10 or more attempts before it will get to point that revs will open up .. then it cuts fine ... but a few minutes later it will start again.

When it is revving it cuts fine with no loss of power.

I have cleaned air filter, checked plug gap, used new (correct mix) fuel, general clean to get rid of any oil or wood chip build up.

Any suggestions?

[Argonaut]

Some more info ...

I just took plug out again ..after today's running - nice biscuit colour so all seems well there.
Used compressed air to blow through carburettor breather pipe back to tank - all clear.

Carburettor is a Zama W26 .... not sure if it has a diaphragm or not, if so I suppose that could be suspect.

[dewaltdisney]

Usually a gummed up jet or the fuel line feed in starving it. It sound similar symptoms to my strimmer

DWD

[kellys_eye]

It's a throttle adjustment problem (carburetor). There are two holes on the side of the machine that have the idle and mixture needles recessed into. It takes a special tool to adjust them but check anyway, sometimes they have slots a screwdriver can fit - most likely not though. It's usually a finely splined shaft that needs a 'socket-like' tool - they sell them on eBay.

IIRC it's the right-hand of the two when looking at the side. Start the saw and start screwing 'in' (clockwise) until the motor stops 'choking'. You'll be surprised at how far you need to turn the adjustment too.

Check out Youtube for 'chainsaw stalling' where there are quite a few video guides to this common issue.

[Argonaut]

do you mean the Low speed screw or the High speed screw .... diag I have found is http://www.zamacarb.com/carburetors/1134

[kellys_eye]

#24 mixture (high speed). There might be a plastic collar around it to stop you making an adjustment though. Best check before trying to wind it in.

[Argonaut]

I did go look on YouTube ,,,, https://www.youtube.com/watch?v=J1ZZvwbJmuw&t=353s
This guy seems to hit the explanation well .. and mine has exactly those symptoms ..... guess I need to find one of those splined adjustment screwdrivers.

[Argonaut]

It's a throttle adjustment problem (carburetor). ... Start the saw and start screwing 'in' (clockwise) until the motor stops 'choking'. You'll be surprised at how far you need to turn the adjustment too.

Check out Youtube for 'chainsaw stalling' where there are quite a few video guides to this common issue.

Took your advice, and looked up a video.
On the video https://www.youtube.com/watch?v=J1ZZvwbJmuw&t=353s
at 3min point he explain turning 'OUT' the screw until it stocks choking ?

[kellys_eye]

In? Out? Shake it all about? Yeah, I might have confused the direction but once you startt 'winding' it becomes self evident - it either worsens or improves.

[Argonaut]

Thanks ... ordered the adjusting tool off eBay so should be ready to play next weekend.

[Argonaut]

Tool finally arrived .... I have removed both mixture screws and cleaned them and the ports with carb cleaner.

Is there a base setting for these screws ... on cars it often 'x' turns back from fully closed ...... anybody got a guide.
I did count number of turns or removal - but they may be way off a good starting point.

[kellys_eye]

Is there a base setting for these screws ...

None that I've ever heard of. Anything on YouTube regarding this? Very much manufacturer-specific I reckon so put them back with the same turns as removed and go from there.

[Argonaut]

Best I found is 'general' 2 stroke carb setting on 1.5 turns out ..... I'll start with that.