038 AVS won’t start

[Coupe]

Check all of what you have been told above but if your carb will not hold
preasure you most probably have something upside down in your carb.
If you have the gasket and metering diaphragm upside down it will be
holding your needle valve wide open or close to it.

 

[PaulMon]

Check all of what you have been told above but if your carb will not hold
preasure you most probably have something upside down in your carb.
If you have the gasket and metering diaphragm upside down it will be
holding your needle valve wide open or close to it.

Ok will do thanks

 

[hacskaroly]

Hopefully this will help if you have any confusion:

It is critical that 26 and 27 along with 10 and 11 are installed in the correct order. 26 has to go against the metal body to seal two holes (opens when needed). #10 has to go against the metal body on the other end to give 11 enough space to flutter, if 11 is down first, it may be pressing against #5 and just letting fuel run through. #11 needs to be put on its correct side too.

 

[PaulMon]

Hopefully this will help if you have any confusion:

It is critical that 26 and 27 along with 10 and 11 are installed in the correct order. 26 has to go against the metal body to seal two holes (opens when needed). #10 has to go against the metal body on the other end to give 11 enough space to flutter, if 11 is down first, it may be pressing against #5 and just letting fuel run through. #11 needs to be put on its correct side too.

View attachment 451836

Thanks, Checked - all good

 

[Woodwackr]

So I noticed that I had a short to earth when the switch is in choke position or warm start.
Can’t see why or how it’s shorting. Cables look good earth goes from the spring to the bolt on top cover. Black cable goes from pin on switch to side of coil. . So anyway, I removed the earth bolt and followed hacskaroly advice of pulling it on warm start a few times and yes, it give a great few positive blurbs. So I used a cable tie to hold in throttle on warm start and it started. It revs up when the arm is in position. . I didn’t give it too much rev in case I’d do harm at this point. Problem now is it won’t tick over. Once I let go of the throttle it’ll die out.

Demon possessed?

 

[Woodwackr]

So I noticed that I had a short to earth when the switch is in choke position or warm start.
Can’t see why or how it’s shorting. Cables look good earth goes from the spring to the bolt on top cover. Black cable goes from pin on switch to side of coil. . So anyway, I removed the earth bolt and followed hacskaroly advice of pulling it on warm start a few times and yes, it give a great few positive blurbs. So I used a cable tie to hold in throttle on warm start and it started. It revs up when the arm is in position. . I didn’t give it too much rev in case I’d do harm at this point. Problem now is it won’t tick over. Once I let go of the throttle it’ll die out.

Well, that would do it. Need to trace all wiring and connections, coil to switch, etc. Check for any bare spots or contact with anything metal other than the intended contacts.
The old harnesses can get problematic and need replacing. I keep wire and the various connectors here and make my own.

 

[PaulMon]

With black switch cable removed at coil, and the ground wire off, I have continuity of 1.2ohms from spade on coil to chassis. This is not correct I take it. Both ground cable and switch cables test good.

 

[Woodwackr]

With black switch cable removed at coil, and the ground wire off, I have continuity of 1.2ohms from spade on coil to chassis. This is not correct I take it. Both ground cable and switch cables test good.

Bad switch, or coil?

 

[PaulMon]

Bad switch, or coil?

 

[PaulMon]

Well folks, i double checked my carburettor and it looked good against the diagrams. Put all back together and replaced the coil and spark plug. I got it started and messed about with the LA H and L and it seems to be performing now ok. I tried to take a video of it ticking over etc but can’t find a way to post it here for your advice. I have it ticking over on a very low rev. In fact it sounds like it’s about to die out but just hangs in there. The chain is not moving when ticking over. When I rev it up it’s straight in and has loads of power. How do we know a safe level of high rpm so not to do damage ?

 

[hacskaroly]

When I rev it up it’s straight in and has loads of power. How do we know a safe level of high rpm so not to do damage ?

Some people can do it by ear, others need a tachometer that clips onto the sparkplug lead. I use a tachometer. Doing a quick look, it appears that the max RPMs should be 12,000 max and it should be idling around 2,800 RPMs.

 

[Wonkydonkey]

You have to load any vid to YouTube or something similar. And post the link here


Hope that helps

 

[Coupe]

Sounds like you may have it idling a bit low. I take them up till the chain starts
to turn and then back it off till it stops. Better idling a bit on the high side than to
low. Some saw quite often start a bit high and as they warm up slow down a bit
or the other way around start slow and as they warm up speed up in the idling
department. Some of the guys on here will tell you as hacskaroly has said
around 2800rpms. Take up till it sounds good by ear and if the chains not revolving
you should be about right. Pleased to hear you have it running, I have had a fair
few problems with the start/stop switch with that model stihl as they get older
they need a bit of twecking sometimes to get them in the run position.
You did the right thing if you are a bit suspect on the switch just disconnect it
from thr coil but remember if that's your problem you will have to couple the wire up to stop
it. Most of the older saws I have arrive in my shed with the guy saying it won't
start and half the time it is a faulty switch either won't start or won't stop so time for a new switch or
clean the old one.