What's on your bench today?

[spudulike]

Hopefully this will be an easy one for you techies to diagnose.

Got an MS200T which when warm can be a bugger to start.

All seems good with it's running - revs out nice with good power, idles steady in hand and on the strop but stop it for more than 20 seconds between cuts and you have to choke to to restart.

 

Any ideas?

Thanks

Ed

 

 

Sent from my iPad using Arbtalk

 

Hi Ed - you and your saws:001_rolleyes: could be a few things - if the compression is a tad low, it can cause starting issues when hot -you can get saws having reasonable power not having decent compression when hot.

 

Other than that - you could try swapping the carb out and trying that! I know you have spares.

 

When you do start the saw on fast idle- does it rev pretty fast on this setting or a bit slow - if slow, lean down the L screw 1/4 turn, adjust the idle to suit and see how that goes -it may be wear in the throttle linkages also giving poor fast idle - the other thing to do is hold it on full throttle and pull the starter with your left hand - if it doesn't start like that than you have other issues.

 

I have had pin holes in the carb pumping diaphragm give exactly this issue and the flaps can get worn/holed as we know!

 

Air leak - possible but would generally give idle/fast speed and holding revs issues!

 

You may have a blocked tank vent - try cleaning it or swapping it out - the tank may get a slight vacuum in it drawing the fuel back out of the carb.

 

It may just be the carb l screw set too lean- one turn is standard setting!

 

Not sure it can be much else!

[Mik the Miller]

On my bench today I has ...

 

An MS880, it didn't come as faulty, in fact it was sold as "in good condition", "seen little use" and "The item may have some signs of cosmetic wear, but is fully operational and functions as intended."

 

 

Well .... it was a bit clogged up with muck-n-sawdust behind the drive sprocket cover (nothing amiss with that I guess), although it was a bit dark. Digging it off the inside of the cover I saw a shiny/indented bit near to the front, above the outer side plate, which corresponded with the holding screw. When I turned the saw over this screw fell out and when cleaned the plate falls off. Closer examination shows that the thread has been stripped .....

 

I noticed that the clutch drum was very dark (blued). I removed the E clip with my fingers (yes it was that stretched) noting that the rim sprocket was worn as was the securing washer. Digging out the crap the plastics around the clutch, specifically the chain brake spring cover, were brown and melted. The clutch was a deep blue. I could see the worm-drive floating about below the clutch (literally) and removed the clutch for a closer look ..

 

The pictures tell a thousand words ...

[Owen Green]

 

Took me 3 hours to build! Just need a load of hydraulic oil then I can give it a good test run!

[div_h]

On my bench today I has ...

 

An MS880, it didn't come as faulty, in fact it was sold as "in good condition", "seen little use" and "The item may have some signs of cosmetic wear, but is fully operational and functions as intended."

 

 

Well .... it was a bit clogged up with muck-n-sawdust behind the drive sprocket cover (nothing amiss with that I guess), although it was a bit dark. Digging it off the inside of the cover I saw a shiny/indented bit near to the front, above the outer side plate, which corresponded with the holding screw. When I turned the saw over this screw fell out and when cleaned the plate falls off. Closer examination shows that the thread has been stripped .....

 

I noticed that the clutch drum was very dark (blued). I removed the E clip with my fingers (yes it was that stretched) noting that the rim sprocket was worn as was the securing washer. Digging out the crap the plastics around the clutch, specifically the chain brake spring cover, were brown and melted. The clutch was a deep blue. I could see the worm-drive floating about below the clutch (literally) and removed the clutch for a closer look ..

 

The pictures tell a thousand words ...

 

What's the big gear below the brake band in the last picture?

[Rich2484]

What's the big gear below the brake band in the last picture?

 

It's the oil pump gearing.

[div_h]

As well as a drive of the clutch drum?

[Rich2484]

As well as a drive of the clutch drum?

 

Hahaha no the drum drives a nylon gear that drives this one that is part of the oil pump

[div_h]

Hahaha no the drum drives a nylon gear that drives this one that is part of the oil pump

 

Ok

[Mik the Miller]

As well as a drive of the clutch drum?

 

The spring is driven by the clutch drum. The spring drives a spur gear (which sits below the clutch) and this drives the planet gear (that's the big gear you mentioned earlier). The oil pump site below this gear and is driven by it.

 

The clutch is screwed onto the end of the crankshaft (left hand thread) so spins at the same speed as the engine. The clutch opens out (gets bigger) when it spins and so grips the clutch drum, which turns the spring, the spur and the planet gear and so pumps oil.

 

Or in the case of this saw, doesn't.

Of course this also drives the chain around and the two are linked really, if the chain is moving you need oil ...

 

The saw (as supplied) is quite dangerous, in my opinion, although the seller doesn't agree

 

I'm not sure how this was damaged, at a guess I would say that the saw was used extensively with a smaller bar (it was sold with a clean 47" Duro) and to stop the chain spinning on tickover the brake was applied. Often. This caused the clutch to get hot, so hot that it turned blue and melted the spur gear....

 

Mechanical sympathy is difficult to teach some folk

Edited April 10, 2014 by Mik the Miller

[Goaty]

Hi all. I assume this has been tackled before on the threads. But I don't know to use really for words in the search. A friend has a husky 235 with the daft tamperproof carb screws. The saw is running silly and not behaving. Is their a simple fix. My thoughts are hacksaw a groove spin them out and get new screws. Any ideas? Feel free to pm me or put it on here for others to benefit. I do have photos to show saw and model numbers. Will put them up later if needed when I get back.