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I think it's the short one, the one closer to the purge valve on carb, not sure right now. If you're thinking switched lines on purge bulb, thats not it because I've done it before and I couldn't even press the bulb easily. It just worked for 6 months and then it suddenly stopped pulling fuel like before. Then it suddenly starts working again.

Bulb is fine, I checked the old one when the same thing happened, it was fine but I bought a new one anyway. Now the same thing happened with the new one too. Apart from the bulb I replaced all the lines too (except the S shaped one from carb to purge bulb, since I couldn't find it anywhere, but it seems fine anyway).

I guess I wasn't clear, there is no fuel coming out, it's just that it wasn't pulling any fuel to the purge bulb. That's happened before. I did a vac test on the purge valve on the carb since I assumed that it has to hold vacuum (another carb from solo 639 that I have DOES hold it). But if as you say it shouldn't, then I guess this is fine? I'll reassemble everything and see if purge bulb works now.

so the only possible culprints could (probably) be inlet needle stuck (replaced that one today) non return valve in main jet faulty Since everything else is new (at most 3 months old and i doubt it would have the same problem as the old parts immediately). When it happened before and purge bulb would not pull fuel, I could fix it by hooking up a vac tester directly to purge valve and making some vacuum. Once fuel got through, it would work for a while. Is it possible to check the non return valve in the main jet? Or would my only option be replacing the carb? As for inlet needle, is that the one that's attached to the spring and was part of the carb kit? Since I did replace that one today, along with everything in the kit (3 gaskets, 2 diaphragms, needle, spring and screen).

it is less than 0.5 bar of vacuum. I just tested a different (older carb) with a purge bulb and it holds vacuum perfectly if I squeeze the intake fuel line. Also since it seems to be worse than it was, even with the rebuild, it certainly seems something is wrong, I just don't know what else I can replace, there is nothing I can see in the diagram that could be leaking and I can fix without replacing the whole carb.

Hello Posted elsewhere, but posting here as well. Still figuring out different stuff that's wrong with my 545. Recently the purge bulb completely stopped working. I removed the carb and tried to vacuum test the purge nozzle like this: https://imgur.com/a/m8VWT7f it was not holding vacuum at all. This is the video from autumn, was also leaking but not as bad: https://imgur.com/a/CSziAIF I bought the oem carb rebuild kit, replaced all 3 gaskets (top and bottom side, autotune unit gasket), both diaphragms, needle, needle lever and screen. It is better now but still leaking fast (worse than the second video, loses all vacuum in about 2 seconds). It seems to be sucking air through main nozzle: https://imgur.com/a/w42csDl Any ideas what exactly could be leaking? I found some info about an oring on the accelrator pump going bad, but 545 seems to not have accelrator pump at all. Pressure test is fine, no leakage at all (and wasn't any before carb rebuild).

A bit of an update on this: First a bit of a backstory: the saw was pinched between tractor and a handle got bent when fairly new. The handle was replaced and it seems whoever did it, used the wrong screw (too long). It punched through the case (either when being installed or sometime later) and was rubbing on ignition coil as in the picture. Coil air gap was also tiny (barely enough for normal a4 paper to fit), possibly the coil was being pushed away by the screw and closer to flywheel. I have now fixed the gap to 0.3 mm and used a shorter screw on this side of the handle and we'll see what happens.

I would but i'm not from UK sadly probably would cost more than that in postage EDIT: would be great for the case as well since brake handle mount is broken 🥲

Thanks, will disassemble again. Ground was attached last time I checked. I'm still somewhat hoping it's not the coil as supposedly it should be hard to start too afterwards, but it's one pull start everytime after dying.

Worth looking into tank vent too? I did additionally have issues with fuel pumping which wasn't solved by new fuel lines and purge bulb. Basically sometimes the purge bulb would just stop working and just pump air.

Regarding spark plug: the cylinder in the picture (original cylinder) had it's spark plug thread stripped. Bought a new cylinder and the same shutoff issue was still present, but it eventually got a piston ring caught in the rough port edges (twice). Rethreaded the original cylinder for a bigger spark plug after, which is the one in the picture. Had to also grind down the nut on the spark plug to make it possible to tighten. Since the issue was happening with two cylinders and three different plugs, i can PROBABLY eliminate a spark plug problem. I'll check out the cables first, then I'll disconnect the kill switch and tape over connectors. I won't be changing the coil as it's too expensive.

Or I could try to check carb wires too if I can find them, but those shouldn't be damaged since they're hidden.

Starts back instantly yes. If it's coil or carb, I can't do anything either, both are way too expensive to buy for this saw, no point spending 200 euros on something that might or might not fix the issue. If it was a non autotune saw, I could just swap over a different coil to test, but here... If I understand it right, it needs to be fitted and coded by the dealer, I can't even find any replacement coil online.

Had some more trees to cut today and the problem reappeared when the saw was decently hot. Didn't even need to turn it to the side, it just cuts out instantly sometimes (for example when putting it into wood). Won't be putting anymore money into it, it will just be a secondary saw for occasional limbing. Almost looks like compression is so bad that it just doesn't have enough when hot. When measured (though my compression tester is a budget one) it was only 85 psi, compared to new 365 xt's 120 psi (assuming tester shows like 20-30 psi lower than it should).

I was only able to cut about three 50cm stumps and some smaller (10-15cm) logs before dark, but it seems to be working fine now, there is no stalling at all and I was rotating it every possible way every minute or so. Unless there really is an oil tank leak and it doesn't happen with full tank. Will see once I have more (and bigger) wood to cut, but then I'll probably be using a 365 for that.