spudulike

Not being funny but if the H screw is all the way in, you have shut off the high speed check valve and the only other way of getting fuel in to the engine is through the low speed jets and these won't support combustion past 1/3rd throttle. Could the carb casting be cracked? It is also possible you have two carbs with shot high speed check valves but it is extremely rare especially on a new carb. Can you try these carbs on another 350? When you take the choke off, is the choke valve completely horizontal in the carb bore? I have seen some carbs get stuck with the choke in a half closed position causing this sort of issue. One other thing on top of the air leak issues I have already mentioned...the rubber manifolds on these saws, as well as 346, 357 etc are often fitted badly and have a deformed or split impulse connector and will cause over revving. Have you popped the muffler off to check the state of the piston? If it has seized but the ring is free, it is possible the inlet skirt is shot and that is causing free porting. BTW....I trust your comment above isn't being a bit glib....you have the benefit of the machine being in front of you!

What are the exact symptoms Mick? Is your machine one of the early ones with the paper stick on serial LABEL (on the black moulding over the top of the recoil cover) or is this laser etched on to the black moulding. I have come across a fair bit of instability on the early ones and once spent a lost afternoon trying everything to resolve it and I mean "EVERYTHING". I didn't find a specific reason but I did develop a very effective cure that always worked for me. I also found that many users had pissed around with the carb adjustment and basically thought they were were somehow trying to find the magical setting with no basic carb tuning skills. In instances like this, the carb goes straight back to the, slightly strange, factory settings which are 85% of the game of getting these machines running correctly. I won't broadcast my fix....I developed it and spent the time to work it out but PM me if you want some help....free of charge!

From my POV, Mark Skyland is often on this site helping out others with their equipment issues. His helpful posts are always to the point...unlike my often acerbic humour....and think this is probably reflective on Mark, the business and staff. He doesn't push his business on the site but obviously just lets it float....we know where he is if we need him! I have used Skylands for the odd Echo part and they arrive exactly as they should. I would think if there was an issue, it would be dealt with in a positive manner from the fact that he is spending his own time assisting people he doesn't know ....same as I do.....I think that is a sign of the character and person behind the business! I hope you get this sorted and soon.

Never mind, I think we both know we both know our stuff

If it was stuck down, the saw would flood and not start. The fella has "fitted a new carb" so it can't be the carb....unless "New" was in fact "different" or "cheap Chinese poop"! Time will tell.

That's what I said last night! The standard settings are 1 turn out but if they are set to 1 1/4 turns each, the saw should run fine once the idle is adjusted. I have only ever had fuel vapour coming out of the carb when the carb is megga rich or the piston skirt is very worn and the pressure in the lower crankcase freeports past the sealing piston skirt back up the inlet port and out of the carb - that was a ported MS660, ran fine before modding but the squaring of the inlet port caused this issue but a new piston fixed it. It appeared the saw had been used for a lot of milling and the filter was pretty worn causing the original piston skirt to wear.

The back fire suggests the ignition timing is incorrect and that the flywheel has spun round on the crank and sheared the key but generally it wouldn't run when this happens. It is however, worth pulling the flywheel off and checking the flywheel, especially if you can do that sort of work. The over revving - in your first video, the saw sounded pretty strangled and no sign of it over revving, when does this happen and if you turn the H screw anti clockwise, does it stop over revving? Over revving is generally caused by an air leak or an incorrect setting on the H screw....just so you know. The 350 is prone to leaking air between the lower engineering plastic cradle and the upper crankcase. This wouldn't cause the fuel to come out of the inlet but would cause over revving. Strange you have over fuelling and over revving together as too much fuel means lower revs as can be seen in the first vid.

If it was like Matts hedge trimmer, throwing it out of the nearest tree for being blunt, not working, not starting, because it is a Monday etc No offence....happy days they were!

Not a bad call if it is the muffler with the spark arrestor!

Funny that, I had an Irish customer, that is a customer in Ireland rather than an Irish fella....that is something different. He had tinnitus from some dodgy muffler front he fitted to his MS660 that had given him tinnitus and wanted his saw ported but not too loud. I said it would be "pleasantly rorty but not excessive". I did my work and he said....."spot on, nice and rorty but not excesive" and goes like a........well, you know the rest. It was and he was happy!

Wood pigeons are a bit thick and inherently lazy....that's it!

It looks like your H screw is wound a fair bit out. Wind it in until LIGHTLY seated and unwind 1.5 turns and try again. 1 turn is usual but am building in a bit of safety until the saw is running better. The H screw is the one on the carb furthest from the engine!

Half a bottle of Chardonnay here....things are looking spiratical!!

Have you had a few? I have and it still makes no sense

I don't believe it exists Andy but...carry on using it if you like!

I am sure it will but will leave you bleeding from the ears as well!

B&W Zeppelin......the little fella has good taste, were you playing the birdie song???

Interesting...... fuel vapour coming out of the intake sounds like a very worn piston allowing the engine to "free-port" past the piston when the piston is on its downward cycle. I am taking that when you have fitted a "new" carb, the needle valve and diaphragm won't be the issue. The over revving on a 350 is most likely an air leak on the inlet manifold and possibly on the join between the lower crankcase and the engineered plastic engine cradle that makes up the lower crankcase - it is relatively common and a full pressure and vacuum test will diagnose the issue. Spiraticly is a new one on me...perhaps "sporadically" is what you mean.....with irregular intervals??? I think the saw needs to be stripped down, the piston checked out and then rebuilt with a full vacuum and pressure test being done on rebuild and then set up with a tach tune at the end....with the symptoms you have.

I think he means the 1/4" pitch bar.

That looks a bit knackered to me....new crank time. You may get lucky and find a secondhand one on ebay.

The tree is so small so not a problem at the moment but in time, it will block out light and fill your house gutters with seeds and leaves and need constant maintenance to keep it off the house. I have silver birch trees around me and in late summer they drop little seeds that get everywhere, they drop small leaves in the Autumn and drop catkins I think..in the spring. I am forever getting them off the car as they get in to every crevice and even blow in to the house through windows and ventilation ducts etc. They are a pain in my backside TBH, and have to say, I really hate them. If it was me...get rid before it gives issue costing £££, grind the stump out and put a nice flowering shrub in its place and keep it trimmed to size - viburnum, ceanothus, choisya and Red Robin to name but a few. Just keep it below 6' which is relatively easy and it will give you a bit of privacy.

Like I said, my thinking is the big end cage has cracked and spat a bit out and that is what is lodged in to the squish band. It will need a new crank if I am right but it is easy enough to check it out. Looks like the cylinder may have survived which is extremely lucky.

Leave the plug out and pull the engine over briskly to eject any oil there may be in the cylinder. Replace the plug, check the oil level and if OK, fire it up and all should be good but check the oil level after a few minutes running. At least we got to the bottom of the creamy oil A bit of white spirit or even petrol would be better to purge it of oil. Soapy water if just dirty with dust.

Looks like the white metal big end cage may have cracked and spat out a bit hence the dent on the piston crown. You can check the cage, where visible, for damage. The cost of the crank and new bearings will be relatively high, the top end doesn't look too bad in the pics and as BMP said, relatively big job for a novice and hope you have splitters, thumping the crap out of the cases and crank isn't dignified!!

I agree with Dan, sounds like emulsified water and oil, the type of thing you get on your car oil cap when the head gasket has failed or water has got in to the oil on old oil. Clean it off, check the oil in the sump is OK, run it up and get it warm, drain the oil and see if it is nice and clean. You can check to see if the crankcase breather runs back in to the air filter...mostly done to improve emissions.