bmp01

3 hours ago, CDMR said:

Investigated fuel pick-up issues but all seems fine. Before I play 'find the bit of the carb that pinged across the workshop', any other thoughts?

There is a tiny reservoir of fuel in the carb so if it really is instantaneous then I'd be looking in the carb for the problem.  I think a pinched fuel line or pick up issue would take a few seconds to show as an issue. 

It could be the metering lever is not operating quite correctly and in need of a tweek - its the only thing i can think of that gravity might affect in an otherwise sound carb. .... but that said the spring should pay the major role in controlling lever position.

bmp01

5 hours ago, lloydh said:

Spud, I agree but I think something's causing that part of the band to leave the channel it should sit in. I have popped it back where it should sit with a screwdriver, but after refitting the sprocket cover and cycling the brake on/off it returns to the way it is now.

I'm not sure there is much to conclude from the damaged band - with that much change to its geometry its going to adopt a different shape to a new one, plus it's bound to have got blinkin hot so it might be distorted too.

I'd be a bit worried about the wear to the inside of the cover (3rd picture) - it says to me things are not aligned the way they should be, could be the cover or the machined face on the engine case. 

It's got to go back for repair / investigation.   I'd be asking for a replacement cover as well as the brake band, hoping that fixes any alignment issue. If that doesnt fix it, then it's replacement saw time.

BMP01

There was a 480 advertised on gumtree earlier in the week, think it was advertised in Corby, 29 quid, missing chain. Probably just a coincidence.

bmp01

Cyclists have a rule that could be applied to saws for some of you lot....

 

Velominati › On Rule #12: The Bike #1 Paradox

On Rule #12: The Bike #1 Paradox. ... While the minimum number of bikes one should own is three, the correct number is n+1 , where n is the number of bikes currently owned. This equation may also be re-written as s-1 , where s is the number of bikes owned that would result in separation from your partner.

Thoroughly agree. The clever bit is establishing what value to assign to 's'.... not got there yet though

3.5 inch between 10 rivet

I asked the question badly. ... think i should have said 10 "drive links" not "rivets"

0.325 pitch per drive link ------> 3.25" for 10 drive links (thats over 11 rivets if you count the first one )

3/8 = 0.375 pitch --------> 3.75" for 10 drive links (or 3.375" over 9 links, 10 rivets - most likely).

My guess is it's a 3/8 pitch chain with a bit of stretch. ... can you confirm, incase someone wants it?

bmp01

Hello,

I'm interested in this, postage necessary though. ...

Could you measure the distance over 10 rivits and tell us the number please? (in mm or inches....)

thanks,

bmp01

Have a look at this thread, might not be exactly the same but nevertheless worth understanding some of the worn carb issues .

http://arbtalk.co.uk/forum/chainsaws/107694-200t.html?highlight=ms200

Also, +1 on checking the fuel tank vent. One way to diagnose if it's this - run the saw until it gives trouble, undo fuel cap to allow air in (ie get rid of vacuum), refit cap and see if saw runs fine for a bit - until vacuum builds again.

How old is saw? What's the service history like?

bmp01

fecked around with this saw again, fuel lines look good, no pinching or splits, cuts and revs fine but either chain creep (fast spin) when saw is level or if backed off til no chain creep, saw dies when hanging on strop.

 

full of fuel. real puzzle. you can alter the revs bypushing/twisting the trigger handle, but i think this is just the carb lever getting pulled slightly.

 

no other ideas? or clues?

 

thanks

So, obviously you've checked the throttle linkage isn't tight sitting level...

Back to the idea that it's fuel related, seems i had it arse about face in my previous post, so does it immediately idle slower when hung up or does it progressively get slower and finally stall? If it were rich at idle (I'm assuming it might well be from that plug) and then made richer it would get slower (and possibly slower and slower until it stalls).

What's the orientation of the carb? I'm wondering if the metering lever and valve are working (but only just) when the saw is level, and not operating when the saw is hung (i know the spring on the metering lever ought to cope with this but if the valves not sealing, who knows).

Solution in this case would be: check the valve, set the metering lever correctly, make sure the metering diaphragm is up the right way and also that the gasket is between the carb and the diaphragm etc. If that's good you could try squashing the metering lever down a 1/4 mm in the name of experimentation ...

Also is the metering chamber vented to atmosphere or is there a compensation for filter blocking?

bmp01

So when I found it looking very neglected and forlorn, to now - with it's new carb innards, clutch, sprocket, chain, filters and a couple of springs and things -

it's back, howling happily in the land of the living.

Top result, well done ! You'll be out scouting for more "fixer-uppers" next :lol:

bmp01

The BN6 mount bars are the universal type to fit all small chainsaws (same as the carving bars). They should still fit the MS201T.

 

Options are:

 

• We can send you a chain x1 drive link shorter and see if this solves it
  
• Grind out the heel of the bar so it is open like the Stihl bar - we'll cover the warranty if you feel this does not work
  
• Or we can send you out the standard 12" sugi bar that runs 3/8 lo pro .050 (as the bar you have I think is 3/8 .043).
  

But with the narrower chain that bar you have should cut faster than the standard 3/8 .043

 

 

Let us know.

Nice set of options for WoodED to choose from

Just looking at the thickness of the bridge (on the bar) and the amount of slack in the chain, if the heel of bar is ground out and the bar moved forward to tension the chain - its got to be touch and go whether the bar will be located by the "screw" that WoodED refers to. Add in a little wear and further adjustment ....

Also what's the situation with adjuster travel?

WoodED take the screw out temporarily, so you can see where the bar needs to sit - that'll answer the question. You could also work out where the bar would sit with a 1 link shorter chain, ie moving the bar inboard by 3/8".

Rob - what's the "known" set up that others have used successfully on this saw? That's probably the best guidance.

bmp01

Knock off 2 more on the opposite side then, that'll fix it. ..

You can not remove that screw, it's the only thing that keeps the bar aligned and stops it rotating around the single clamping stud. Have a look at the wear pattern on the screw where it contacts the bar that tells you it's doing a job.

If it were a cheap old bar you might consider cutting the slot right out the end (like the Stihl)....

bmp01.

Bmp01

A hs45? Gearbox just went on eBay.

 

 

Sent from my iPhone using Arbtalk

Thanks for the thought.

It's a long reach HL135 hedge trimmer with the usual rod bearing failure due to a lack of maintenance. I should probably just bin it really. ...

bmp01

Wow, how is she not dead ? ? ?

So here's the thing, how do stupid people get away with stuff like this? Anyone with half a brain would be so tentative it would have gone wrong ....

Is there some sort of higher power looking out for stupid people or something?

I have a mate who only uses farmertec/Chinese

Parts in his stihl saws.

Not precision engineering I'm afraid.

Low compression in the pistons and cylinders.

Constant problems and they don't last long either.

Even things like plastic tubing splits and cracks.

The metals are often unhardened or just soft.

No uv resistance on the housing plastic either.

Not to mention the safety features are just copies and might not work.

Oh one last thing, go on YouTube and look up safety testing stihl copies.

IMO absolute lethal rubbish.

[emoji107][emoji107][emoji107]

 

 

Sent from my iPhone using Arbtalk

I was looking at Farmertec gears for Stihl hedge cutter gearbox. Number one requirement has to be material quality and correct heat treatment. So thats another good plan down the drain then. ...

bmp01

When I opened the carb up there wasn't a fuel screen in it so I can only assume someone has been there before me. I put a new one in.

Thats never a good sign - fuel screen missing.

When you spray through the low speed adjuster hole you should see the spray coming out of the tiny jet holes in the carb port - 2 or 3 jets up stream of the throttle plate. Make sure each hole is flowing.

Spraying through the high speed adjuster hole, spray will come out of the main jet (brass cylinder protruding into the carb post).

Some folk like to use compressed air to blow through the passageways but Id be cautious of that. Sometimes the main jet has a rubber disc in it which needs to stay put, fuel screens can be dislodged, even the welch plugs ....

HTH.

bmp01

No I didn't touch the screws at all. The saw had been running fine and then started not wanting to rev from cold. Then that problem got worse, difficult to start past an initial cough. That's when I asked for thoughts at the start of the post and took the advice to change fuel line and service the carb. But as Spud noted, I didn't unscrew the H&L screws and clean inside these, so that's next.

 

The gaskets and membranes inside the carb looked fine though. However the gasket between the carb and the saw body looked rough so I changed that.

 

I'll see what happens with a more thorough clean of the carb.

Spuds the man. I hadnt even considered you might have left the screws in place !

Worth gently winding the screws in first and noting number of turns it takes, sometimes gives a clue when you know where you are relative to the factory start point, (the 1 - 1 1/4 turns out).

Just winding screws in and back out is sometimes enough to reset the clearances but if you have the time do it right.

After a long while I've finally replaced all the gaskets in the carb, cleaned it out, replaced fuel line.

 

The problem still persists. Saw won't rev. It'll start fine and tick over (just) but as soon as I touch the trigger it dies.

 

Anyone got any thoughts what to try next?

Have you touched the low and high speed mixture screws at all?

Take a note of screw positions before you start.

I'd turn the low speed screw out a 1/4 turn anti-clockwise (= richer) and see what that does. You might get away with less. It might also need the engine speed screw winding in slightly (to increase speed) at the same time just to keep the speed the same.

When its up to temperature do the low speed carb adjustment properly. And high speed if you know what you are doing.

bmp01

Stevie,

No point trying to stop you is there?

Small practcal point then. After you have done any work on the saw, reassemble but leave the chain off. Last thing you want is for the saw to be revving its nuts off, chain flailing round while you try and figure out why the ignition kill doesnt work.

Come to think of it, how about taking the chain off first thing, before you do any work on it. Start the saw and get used to the feel of it, get used to the controls etc.

bmp01

Magnets seem good in the flywheel. I'd have thought putting the coil pack and plug from the MS211 would give me a spark but doesn't seem to.

It's a good method of fault diagnosis - swapping in known good parts - and there ant that many parts in the ignition system so yes should have worked.

Leaves you with limited number of reasons why it's not working -

- remainIng unchanged parts at fault, flywheel, wiring etc

- you've installed the known good parts incorrectly, possibility of a short?

- Known good parts have gone bad in the transition or been broken during assy.

- known good parts not compatible, alignment issue with / without spacer?

I'm grasping at straws...

You could try the reverse, put the old parts on the 211, one at a time, might help to narrow down the suspects.

Is the 181 barrel a genuine one by way?

I dont understand this either. The only other component to change is the flywheel. But quite how that could go bad i have no idea.

Probably arcing internally somewhere when it achieves the required voltage, insulation breakdown. ... But it could be generating a voltage upto the point where it arcs internally and maybe that's what the tester is telling you.

Of course if the voltage when insulation breaks down is not high enough to create an arc across the air gap of the plug then the plug never sparks. You could try closing the plug gap down to 10 thou, 0.25mm, it might arc.

Arcing could also be from the plug lead or plug cap, especially if damaged and dirty. Plug lead will be integral to the coil on these no doubt though.

bmp01

Damn !

I was really hoping there was going to be a magic answer to save me from my least favourite chainsaw job. .... really disappointed

I've found a bucket of hot water with a splash of car wash stuff (traffic film remover) does a good job of softening the goo and breaks down the oil - plastic parts only, honest . Often need a bit of a brush as well, and an airline.

Parafin works too, leaves it a bit oily though.

bmp01

 

Same problem though. Petrol not reaching the cylinder. Fires up with fuel injected into the cylinder through the plug hole.

 

Should you be able to blow through the petrol carb intake, using your mouth? I can't.

 

While you are doing what Spud says, with the metering chamber cover off, try your blow through test and lightly press the end of the metering arm at the same time (so you are manually opening the metering valve). That should allow you to blow through the pump side of the carb and through to the metering side.

bmp01

bmp you point at the 3rd post...I'd love a 036 for £120, but that is an absolute steal. I'd be suspicious about any saw on Gumtree, either that saw was nicked or it was a non-runner at that price surely? and also don't know enough to determine what might be or might not be seriously broken with a non-runner, or with a runner for that matter. That poster admits to CAD (=Chainsaw Addiction Disease) so probably knows a lot more than I do.

I was quoting the third post primarily to point out that the saw you were looking at it isn't popular here, rightly or wrongly. ...

In view of that 'fact', I suspect you are flogging a dead horse trying to get an opinion on the specific weak points of that model, with your intended type of use.

About that Stihl 036, yeah of course it was a bargain and no point going looking for that exact saw. Neither is it worth looking on that auction site IMHO, the audience is too big for good deals and the asking prices are usually top dollar anyway. But Gumtree, local ads etc can often throw up a deal or two so long as you are flexible in what you are after.

Are you in a position to make an informed second hand buy? I'd say so, you've used a saw for a start, you know how they should work, you'd recognise a maintained vs neglected saw. Buy locally, get the saw demonstrated and try it for yourself. I think there are a lot of good saws for sale that just don't get used for various reasons.

bmp01 (also an engineer, also inflicted with CAD).