bmp01

It's all true. T'is the way of the world. Cheap means when it breaks you DONT mend you bin it and buy another. Being a sucker for this kind of thing, I've repaired a few, and tuned them too. My 211 runs a cylinder pressure of 190 psi, achieved by moving the crank centreline ! A muffler mod gives a big gain in percentage terms too. To remove the seized aluminium from the cylinder i use a sanding drum and 120 grit emery cloth. I make the diameter of the drum approx 1 mm smaller than the bore to avoid a too focused abrasion. I try to move the drum around the area of deposited aluminum and at the end of the process put a cross hatch finish in the bore. Pictures of drum and a finished bore attached. bmp01

The clamshell engine only has one split line and that is horizontally through the crank centreline. ... the crank has to come out in order to get to the piston. The basic strip down procedure - remove the front handle, then remove EVERYTHING attached to the engine, apart from the intake manifold and plastic divider thingee. Finally undo the 4 bolts holding engine into chainsaw body, remove engine incl intake manifold etc. Just a note of warning, the engine pan (lower crankcase) is only held on to the cylinder with the sealant at this stage. (Its a s**t design imho, dunno how they are assemble them in the factory with out the worry of the engine falling apart while fiddling it in to the the chainsaw body). bmp01

Actually the Meteor web site is pretty useful, have a look here Meteor Piston Gardening - Forestry Products Catalog I've copied a couple sections from the catalogue, first one is only useful to see the column headings. Second one you can compare the piston dimensions for the MS230 and MS250 pistons. The top of the piston to the gudgeon pin centreline (18) is the same in both cases. The gudgeon pin is the same. Only the diameter and length are different. I'd ask the question to confirm but it looks to me like the MS250 would fit you cylinder spot on. bmp01.

I bet the Meteor piston for the MS250 would be the right one. Stihl spec for the European MS230 says it has the same bore and stroke as the MS250. If it were my money I'd see if the barrel would clean up - it looks genuine Stihl. And ask Meteor directly (Meteor web site has contact info) if their MS250 piston can be used in the Euro MS230. Also ask what the pin to crown dimension is and compare with your chinky piston (but remember your chinky piston isn't guarenteed to be right). That approach costs you under 30 quid. bmp01

Just a thought, what do you know about the saw history, is that the right genuine piston? Rings look pretty free for a seized piston, seized on skirt so lubriction issue - old fuel or straight gassed. bmp01

Yeah, i saw the cast '42' With regard to measurements and from your picture, the piston looks pretty well trashed, do you think you are managing to measure a true diameter using undamaged surfaces? A measurement inline with and below the gudgeon pin looks about the only plausible place.... Apologies if I'm labouring the point ! I have a new piston for a husky here in front of me, made by Golf, (horrible thing but that's another story). Measuring diameters it's 37.78 at the crown, 37.95 on the skirt. It fits a 38.0mm barrel. I also have a seized ms260 piston, heavily damaged on the exhaust side. It measures 44.5 just below the second ring inline with pin (only place without damage), and 43.5 across the skirt ie. 1.2 'ish mm of wear as barrel is 44.7 mm. The way i see it, your piston measures a worn 42.0, you need allowance for thermal expansion, so barrel is probably 42.5 as that matches a MS230 spec. You either need to cross reference part numbers to confirm you have a genuine barrel, measure the barrel. Or just try a 42.5 piston on a suck it and see basis.... I can't help with part numbers, sorry. Look/ask for a parts list. bmp01

Which end of the piston did you measure? Top of the piston is reduced diameter to take account of the expansion as it heats up. Measure the skirt end, in several places and away from the area that seized. And if you can, measure the barrel or find something the right diameter and see if it fits. I expect it is a 42.5 bore, that was what was in the spec. But, I've been wrong before! No idea what Meteor sell for this model. ... If you are lucky you can some times pick up a second hand piston over on that auction site. A used, good condition, genuine piston is a good option in my opinion. Got any ideas why your saw seized in the first place? Good luck, bmp01

Well. .... my first assumption was 'no' You wouldn't change the spec that much and keep the same model number, surely. But i googled MS230 Owners manual - there's usually a spec page at the back of the manual. Hopefully I've managed to attach a screen dump of the spec page. Sure enough there are 2 bore sizes, 40.0 and 42.5 so the answer is 'yes'. Time to have a chat with your supplier? For what is worth; The A stamp I understand to be a tolerance band based on the nominal size. It allows the manufacturer to match up piston and barrel size with out making every batch of parts to a very tight tolerance. So for example if the batch of barrels is 0.010mm bigger than the nominal size, then pistons oversized by 0.010 are used in engine assembly using those barrels. That said, i don't think i have ever come across anything other than 'A' graded. HTH. bmp01

Old engine oil is ..... and for all the reasons mentioned above i dont think i would want to use old engine oil either. Old gearbox oil on the hand isn't (carcinogenic) as there are no products of combustion contaminating it. I raised the question about 'gearbox' oil... Not really of much interest I agree, I only raised the question because the viscosity is similar to bespoke chain oil (unlike engine oil). I'll try it at some point. bmp01

A bit off subject but as we are on different oils, I've got 3Ĺ of used gearbox oil, seems a waste not to use it for something. ... anyone any experience? It's pretty viscous but probably in between regular chain and engine oil, approx SAE 90. No idea if it has any anti fling properties. Probably not good for the environment. Thanks, bmp01

Yep, it is , so it is...

Nope, thats wrong. .. Got a little bit more info. .. Its ARG 6224 (not 4224, which is what i had interpreted too). Goggling ARG 6224 gets a perfect match with a secondhand. .... wait for it.... Sovereign (thats homebase isnt it?) on that auction site, link below. I don't know if that means it's made under licence or more likely a just a rip off of the Komatsu Zenoha. Plastic around the bar nut looks sore/brittle on the eBay one, so that probably explains the need for the alloy plate around the bar mounting. Thought i should update the thread. But all of a sudden I've lost all interest in this SOVEREIGN - USED PETROL CHAINSAW ,WITH 16" - 40 CM GUIDE BAR | eBay

Looks like a good match to me - different colour scheme and probably a later model but very close. Komatoso Zenoah brand it is then. Well done and thank you bmp01

Yes, i have asked for better pictures and waited, and waited....then i thought someone here would probably just know. Grey throttle trigger and safety must be a clue. I wondered about Efco but red controls on the 136 model. Thanks,

Hello, Not sure if this is good practice. .. if not I'll request the thread is deleted. What's this saw ? Obviously too much plastic. But I was interested to see what looks like an alloy plate to bolt the bar to, might be the plastics weren't up to it when it was made. Certainly not the cheapest way to do it though, so at least some attempt at making a more durable product. Thanks, bmp01

Come on then, spill the beans, what was wrong with it ? Or have you been distracted with tuning your other saws Let's us know. .. bmp01

It's been 3 months, nearly there then. ...

Original post says "Have used my 028AV over about 10 years for domestic tree felling and woodcutting. " = Weekend Warrior. Nowt wrong with his choice of saw for his use, 028 He is an engineer, I'm sure he'll get some satisfaction from fixing the thing

Thats a detailed analysis. But have you done Spuds suggestion in post 10 - I think its a very good test to answer some of your questions regarding fuel supply to carb. Start with clean, empty carb on the bench. Refit. Turn engine over - with out choke. Remove carb. Inspect for fuel in pump and metering chambers. If no fuel, you have the answer to your question. 30 mins tops. Ditto with my suggestion above. Have you checked the tank vent hose. Blocked vent would surely allow engine to run normally for a few minutes while the tank gets into depression, then no fuel. Another suggestion, you may have reblocked the filters in the carbs again. I have suffered with my 028 with a mystery gunge / slime that reappeared after the carb had been thoroughly cleaned. PM me regarding tech manual if you want, but the answers here will teach you more:001_smile: And please keep us posted when you find solution. bmp01

Fuel tank vent blocked causing vacuum in tank? Unscrew the fuel cap to vent the tank.... will saw restart? IIRC Fuel tank vent hose has two grub screws in the line with a jet sized hole through each, its situated behind the air filter. bmp01

Here's what i do, generally works for me, probably more definitive guides available elsewhere . .. Low speeds first, I generally start meddling shortly after the saw has started and assume fine tuning might be necessary at later date. -Idle speed set a little below where chain rotates. -Adjust low speed screw to give highest idle (steps of 1/8 turn initially, pause at each step for a few seconds for speed to stabilise). Then richen up by 1/8 - 1/4 turn, speed drops a little and often not quite as smooth but the saw will be more responsive here. -Reset idle speed. You can check saw response at this stage, may need to go slightly richer if the saw doesn't pick up cleanly. Make sure the saw is reasonably warmed up before giving it too much grief with the high speed adjustment. High speed, no load, chain fitted and tension adjusted correctly, the saw should be 4 stroking and sound pretty rough, you do NOT want it to run smooth and scream, that is asking for trouble. The previous Youtube video is a good one to learn what 4 stroking sounds like. -I start deliberately rich, hold the throttle open for a second or so but no more, determine the 4 stroking, adjust leaner 1/8 turn and retest. Continue until the 4 stroking is only just there. Repeat the low speed settings, they won't be far out, stick with a slightly rich setting. Repeat check of saw response. Repeat the high speed if you made changes to the low speed - confirm its 4 stroking. Test cut in wood, you're looking for the 4 stroking to disappear as the cutting load brings the saws speed down slightly. Easiest way to listen for this - during the cut, continue to hold the throttle open but just lift the saw away from the cut. Speed will go up and the 4 stoking should come back, sounds horrible ! If in doubt richen it up a little. Saws with speed limiting coils must not be tuned in this way, safest is to use a fast response tachometer. Saws with the strato engines are also less easy to tune by ear in my limited experience. HTH, bmp01

+1 Seems the only sensible solution to stupid tamper proof screws. P.I.T.A screws ?

Hello, Worth a check to see if the carb has been assembled correctly - might have been assembled wrong before you got it ? Just thinking, using choke you are pulling the fuel through the carb with the depression of the induction stroke. .... Off choke you are reliant on the pump in the carb and the metering chamber working correctly. I had the same problem, had me stumped for a bit, found the metering chamber diaphragm upside down, so it didn't open the metering valve. Sadly, it was a self induced problem Good luck. bmp01

Thanks for reply. Agree 100% - but (apart from 4 meteor pistons and 1 golf piston) thats based on what i have read here, a lot of it from you :biggrin: Contacted both sellers, Pistons from Tesgol are made by VEC, India. Danikrop didn't disclose manufacturer but said they are made in Taiwan. I'd be happy with Meteor or Episan but these are not available to my knowledge. Didn't like the Golf piston (for husky 136). I have no idea about the above two. .....was hoping someone on here had some direct experience ??? Thanks,