spudulike

The 340 has the top crankcase moulded in to the lower part of the cylinder making it a typical "Clam" type engine so modifying it with a 346XP cylinder isn't possible.

The 350 however, has a separate metal moulding making up the top crankcase and this gives it a flat base where the 346XP cylinder can be fitted and is a known mod although I have never done this.

Both the 340 & 350 have a plastic cradle that the metal parts are bolted to and the lower crankcase is formed by the plastic cradle.

This IPL will show you what I mean: -

340_340Е_345Е_350.pdf

On the circlips with no tang orientation.....When you purchase an OEM stihl piston, there will be one circlip fitted and the open gap will face upwards to the crown of the piston and that is how I always fit this type of clip.

33 minutes ago, Trailoftears said:

I'm glad its all sorted.Just out of curiosity,why are some circlips tanged and some not? Is it just to help with fitment problems?

The tanged ones are easier to fit and remove but the danger is that the tang may wear in time and break.

Most of the aftermarket circlips are decidedly iffy at best. Compared to OEM ones, the OEM ones are much harder and springier than the aftermarket ones that can be easily deformed if care isn't taken.

That is strange, the circlip looks like a Stihl one and they never fail. It is most likely that it was either not fitted correctly or damaged on fitting. I usually fit them then rotate so the open part faces the top of the piston and then inspect with a magnifying glass to ensure all is 100%. 

Very east to think it is fitted correctly but the thing isn't sitting in the groove correctly.

As above. I used an awl and used another screwdriver as a fulcrum but a very similar method. You have to be careful not to pierce too deeply as the ball race is under the seal but it can be done and it works without any major expenditure on special tools.

Try making the L screw a bit richer. The H screw is for flat out running whereas the L screw is for idle to mid revs.

Yup, as OS said, Stihl never used tanged circlips but thanks for the update and glad the saw is up and running again.

On 13/02/2024 at 19:51, spudulike said:

I reckon that putting the choke on is pulling through a lot of fuel which has a similar effect to how you adjust the H screw to keep the revs down at flat out running. The very rich mix will stifle the engine at idle thus keeping the revs down. 

You have a real big air leak so a split impulse line, a crank seal that is seriously worn/degraded, loose cylinder, damaged crank case etc. It will be that big that it should be quite visible.

Oh bugger....right again!!

On removing the seal, you can pierce the steel part and lever it out, use the comfortably expensive Stihl kit....yes, I do have one but piercing it and levering out may be the cheapest way to do it.

Great, glad you got it going and thanks for letting us all know.

On your point 5)  : -  the dry plug will be down to lack of vacuum in the crankcase....the fuel vapour is pulled in to the engine as the piston rises in the cylinder, this causes a vacuum in the crankcase to increase and pull fuel/air vapour in from the carb and enter the engine via the inlet port. Because your piston was so scored, the piston rising in the cylinder caused a substantial lack of vacuum in the crankcase so no fuel on your spark plug.

An engine can get a big air leak in the crankcase and still have "secondary compression" (combustion chamber compression) but total lack of fuel due to the above. A bit different from four strokes and is why I bang on about vacuum and pressure testing the engine as well as a compression check on the top end  - The crankcase has both vacuum and "Primary compression", the top end is known as "Secondary compression" but is often the only type mentioned.

Yup, ADW pretty much has it and a good recovery by you. The heat drives off any excess water around the saw, best thing you can do.

I have seen the needle bearing get a bit rusty when wet so get a bit of lube on it just to make sure

L&S are a decent outfit. I have never had any issues with them over the 12 years of using them.

On bit of advice is to fit OEM circlips and make sure they are 100% in their grooves and the gap in the clips is to the top.

L&S and Garden Hire Spares are now in business together....Wartec were a GHS brand.

Oh dear, here we go again. How will this one end 🤔

So the "Eggs" nickname lives on to be used again......get well quick but a broken wrist is a bar steward, lots goes on in that joint and full mobillity will take a fair while - the Mrs did hers on a muddy field path....took a while to get it back to normal.

Looks like he has renamed his trading name but that is the fella alright. Usually takes around a week to come in the post.

One point - the 038 came in several variants with different size pistons - not a problem if you are purchasing a complete top end kit though.

All I can say is..."I did say" .....the times I have heard....It has compression

It did look like the top ring location pin had come out in one of your pics but the damage is obviously from the circlip tang. Make sure the part isn't in your main bearings.

You will need a new cylinder and piston. My first choice is OEM if you can get hold of one, followed by Meteor, followed by Hyway (use OEM circlips) and then you get down to VEC/GOLF and then no brand. Use Stihl circlips on all but the Meteor kit.

When you reassemble the bottom end, make sure you "de-stress" the bearings. Don't sent them on a spa weekend but do bash the crank on both ends with a copper mallet a couple of times. You will notice the crank will rotate much more smoothly after doing this. Failure to do it will damage the bearings.

The bloke in Greece is a good seller...something like "Danicrop" but called Leo I believe.

Yes on the carb sounding OK, it may still have a check valve issue but if you spray a bit of carb cleaner or even WD40 through the carb with the throttle open, it should fire if you pull it over plus it should flood if you keep pulling it over on full choke. If this isn't happening, it sounds like the check valve is jammed shut which is relatively unusual. You could remove the H screw and spray a bit of cleaner down its hole.

On the spark, it sounds OK - you can open the gap right up on a spare plug and see if the spark can jump the gap OK which will test the spark strength.

It does sound carb related from the plug not getting wet but also the stopping instantly also sounds like HT system but the saw should fire if you spray cleaner etc through the carb as previously said...a bit strange.

Try undoing the H screw to 2-3 turns and pull over on full choke and see if the plug gets wet after 15 pulls or see if it even tries to fail. I guess the choke is shutting correctly and the high speed mechanism kicks the throttle valve open as it should.

I left out one thing, the bottom of the con rod (Big End) will often blue up if it gets pretty hot. You can do all the tests I mentioned to verify a failed big end without splitting the crankcases. Hopefully one of your mains has grenaded as it is a bit cheaper than a new crank.

The crank is shared with the 461 - I repaired one with a secondhand 460 crank saving the owner a decent amount of dosh in the process.

If the first chamber (Pump Section) is full of petrol, the carb is pumping fuel up from the tank. This may mean that the impulse line is working fine but a machine can run without it if their is positive pressure in the fuel tank...warm day etc.

Fuel in the second chamber (Metering section) means that the needle valve is working OK and the carb is letting fuel through so it can be drawn up in to carb bore to enter the engine.

You say that the plug isn't getting wet, is this with trying to start the machine with the choke on? With the choke on, giving the saw 10-15 pulls should pretty much flood the machine. 

You say the saw engine has pressure and vacuum - if you have a BIG air leak in the crankcase, it can cause lack of fuel...was it checked with a vacuum and pressure pump etc.

The kill switch description - the lack of contact would stop you from stopping the machine as the system connects the coil to earth to stop it. If you want to bypass the kill system, disconnect the kill wire from the coil and try it again. Closing the gap up to the very minimum, ensuring the two don't hit each other, can help maximising the spark, especially on weak flywheel markets and weak coils.

Basically, you need spark, compression and fuel...compression is usually the first one to check....what is it measuring? I have heard..."Has Compression" too many times to find the piston has seized and all you have is friction and NOT compression - whip off the muffler and take a look.

It may well be the big end. Check for play in the bearing - Up and down not sideways. You can usually push the con rod big end to one side with the big end cage pushed the other then rotate the cage round with a craft knife or similar. Look for cracks and missing bits on both sides of the bearing cage.

Not a nice outcome but a good learning curve for the future.

I think your £150 maybe a pretty light estimation.

One little plug - the own baked full grain brown loaf from Tesco punches truly above its weight. Been through many big brands and bakers loaves and this single loaf is as good as Days the bakers (Hertfordshire) GI loaf. 

Pate, with soup, sea food/prawn sandwich filling...pretty much anything is good with it.

There are a decent amount of pumpkin seeds in it that make a big difference.

The loaf comes in a clear bag with the own printed Tesco label and bar code if you are interested - you can find it on their fresh bread racks near the bakery section.

£1.45 for the big one - bargain IMO.

23 hours ago, pleasant said:

Smoked salmon and cream cheese. Nicely buttered on good quality brown bread. 

Blimey....what is your hourly rate

If you look at the link between the two cutters, the rivets are slightly polished and this is the link that joins the loop of chain hence the possibility of not having opposing cutters.

3 hours ago, Botty Cough said:

Not until we live in the world of mad max will that get funded 

Will that mean we can rip round on Z1s and GSX1100s with the last 1.5' of the exhaust system missing wearing scabby leathers.......Lovely

If you have flooded it, not wishing either of us to suck eggs.....remove the spark plug, turn the ignition OFF, turn the saw upside down and pull it over really hard a few times. This really helps clear puddled fuel and you may see it drip or spatter out of the saw hence the ignition off and YES, I have seen this ignite one one occasion - pretty impressive but not good for hair on arms or eyebrows!!!

I also find heating the plug up with a plumbers torch or gas cooking hob can help with getting the engine to fire but get it in and pull it over quick....no choke but fast idle position.

At least a working module will prove if it is that or not. Has he got a good carb to try? 

Probably easier just to grind and file the mushrooming back to sort it unless you want that look.

I think your spell check kicked in...It is Brades Co not "Braces"....a decent manufacturer.

The wedge - take a 3mm drill and drill the wedge out bit by bit. You may get lucky and be able to lever it out. There may be a metal wedge in there, nails, screws etc but if you are lucky, once the wedge is removed, the handle will knock off there the slot can be cleaned, a new wedge cut and planed to size then fitted.

As I said, use some PVA wood glue to get a good bond and knock the wedge in good and hard then cut it to size.