Bensmith

Thanks Spud, I also keep coming back to the carb and would be happy to replace the harness and solenoid again but if it’s not that it can get really expensive quickly so was thinking maybe an mtronic diagnostic would show something helpful. My local dealer has to send it away to their sister company and my next ‘local’ dealer generally only offers it as part of the repair process so couldn’t give me a price and won’t do it while I wait so its over 120miles, a day gone and whatever they decide to charge me. It seems I back to the option of throwing new (and old) bits at it! So I put the old solenoid back on and it wouldn’t run long enough to do a reset again so the new solenoid definitely makes a difference, but I guess I still can’t rule it out. It looks like the main problem with the solenoids is they get worn/blocked by tiny particles and can’t work properly but as my new solenoid was like this from the start I can’t blame it on wear. Before I order a harness and new solenoid could you confirm that the green solenoid is the right one for a 2018 201 TC as there are also the black and white ones available and I can’t seem to find a decent post explaining the differences.

I'm still wrong and you're right it's the pump diaphragm I've been calling the reed. Gaskets checked and in the correct order, i tried flipping the metering diaphragm and it may have made it a fraction better but after a reset its the same The fuel line, filter and tank were all given a really good clean, its on the standard white filter but running it with a much less restrictive filter its the same. I don't have a way to pressure test the fuel lines other than with my mouth and some carb cleaner and it seems ok. I've opened up the exhaust outlet so when i blow through it the resistance feels about the same from each end so about twice the original size, it definitely sounds a lot happier and feels a bit more aggressive but no idle. There's continuity on the red and yellow wires from the coil to the carb connector, i couldn't see where the black one terminated and completely forgot to check the carb side of it so will have to keep you posted on that one. I thought someone said a wiring fault is either intermittent or just wont work, my issue is consistent no matter how much i prod and poke those cables. The flywheel gap is about .2-.3mm, my feeler gauge has seen better days but what should the gap be? The plug spur is well connected and doesn't look yanked, it has a reassuring click and again holding it in or wiggling it around it runs the same. There's a slight dint in the HT lead where the retaining screw has compressed the plastic and i cant check the rest of it without removing the fly and i need to make a puller for that. The spark isn’t really saying too rich or lean it was possibly a bit rich on the no6 plug so I put a no7 in it and seems possibly a little lean now but well within old carb parameters on both Thanks, I know I shouldn’t do it but I feel a bit stuck because with a standard carb id just up the idle and or adjust the L on the carb and it would either give me something to work from or just work again but I can’t do that with this one other than forcing it with the idle set screw on the carb which is fine for a while but the mtronic seems to learn and the problem reoccurs and I up it a bit more to the point where when I set it back to “factory” after the full carb clean the screw was nearly 3 turns out so clearly not a solution.

Thanks Spud, lots to digest here, I think I’ve been calling the metering diaphragm the reed It was a kit, i changed the gaskets, diaphragms and gauze but not the needle, arm or spring The piston looks cleanish and not scored but I’ve only looked through the exhaust and plug ports. I’ve only run it with the pulse line off for testing purposes I wouldn’t use it like that, I was surprised at the strength of the jet, I was expecting more of a puff but ill check the rest of your suggestions and get back

Other than the lack of idle it’s a great saw, the throttle response is amazing compared to my 1978 015 and it will eat through up to pretty much any 8” log without breaking a sweat, its logged up at least 10 cubic M for me this summer and happily devoured the lot, I just wish it would idle so I can take it up a tree and be safe

Thanks, I feel a bit stuck because with a standard carb id just up the idle and or adjust the L on the carb and it would probably work again but I can’t do that with this one other than forcing it with the idle set screw on the carb which is fine for around a tank but the mtronic seems to learn and the problem reoccurs and I up it a bit more to the point where when I set it back to “factory” after the full carb clean the screw was nearly 3 turns out. The spark isn’t really saying too rich or lean, it was possibly a bit rich on the no6 plug so I put a no7 in it and seems a little lean now

The pulse line looks fine, at the moment it only wants to idle with the line off! So I guess a question would be why would a saw run without the pulse line? I assumed it needed the pulse to regulate the carb.

Hi everyone, my 2018 Stihl 201tc (mtronic v2 i think) wont idle, it starts cold every time and mid to top revs runs a treat but when it dies i often have to restart it on full throttle. I changed the solenoid (the old one was black and new green) first which enabled it to do the 90sec reset (which I’ve done every time changed anything) but still no idle so next i changed the diaphragm and reed, spark, fuel and air but no significant change. Because I changed only the solenoid first there’s a chance I blew some rubbish back into the diaphragm chamber which then contaminated the new solenoid but I have since redone the whole thing in one go with a good clean and it’s just the same I can force it to idle by turning the “old” idle set screw that’s thread locked in the factory but it’s rough and not a permanent solution unless at extreme altitude and im at sea level. It will idle perfectly, rev up well and not cut too badly with the pulse line off but as soon as i put any resistance over the crank side it dies and if I block the carb side it dies after a few min on idle. If I loosen the exhaust bolts it will also idle but with the exhaust removed the idle is erratic, so I did the mod hoping it would help but it didn’t. Any thoughts on what’s causing these symptoms would be appreciated, thanks