Still MS170 chainsaw hard to start & doesn’t run long

[ipbr21054]

I started the saw yesterday & let it run a while & all was fine.
Today I went to the job just down the rd but it was a pig to start. Once started operating the trigger didn’t give me much hope with what I could hear.
It then sounded fine & I started to cut some logs but after say 5 minutes I knew soon it wasn’t going to keep running & in no time it stopped. I pulled it over 10 times but nothing.

I went home & removed the carb & cleaned it.
A few pulls but nothing. A drop of fuel in plug hole & a ew pulls it started so I let it run a minute or two.

Back to the job to finish off the last few logs but I wasn’t even there 10 minutes & stopped again.
Pulled & pulled but nothing so I went home.

So looking at the air filter it’s a white cotton wool looking flat piece which is soft as opposed the rigid type I’ve seen. So I’m thinking I wonder if some dust etc got passed it & into the carb ?

I’ve just ordered another air filter & plug.

I did remove plug & hold it to the cylinder & im sure I seen a spark due to this daylight.

Does anything spring to mind or what should I be now doing.

In the last 5 years I e owned it Ive never had this issue.

 

[Murdochcat]

Is the filter in the fuel tank blocked / needing replacement?

 

[ipbr21054]

When i removed the carb i unscrewed the fuel cap then blew down the pipe & could hear it in the tank so i would say no its fine

 

[Murdochcat]

When i removed the carb i unscrewed the fuel cap then blew down the pipe & could hear it in the tank so i would say no its fine

To inspect this properly you need to “fish” the pipe and filter out of the tank

What colour is the spark plug?

Did you put oil in the fuel tank by mistake ?

 

[ipbr21054]

Petrol & oil mix.
Plug seems ok but maybe dry

 

[blup]

Maybe the carb or carb linkage

 

[ipbr21054]

Carb linkage is free & not jamed.
Carb apart & was cleaned but doesnt mean its 100%

 

[Burnerman]

The MS170 does use a flat felt air cleaner - nothing wrong with that so long as it's clean.
If you thought the machine was losing power, turn the screw marked H anti clock a 1/4 of a turn.
Does the machine return to idle?
I'd suggest replacing the carb diaphragms or maybe finding a replacement.......they don't like E10 fuel either! Always go for the Aspen type pre mix.
John

 

[ipbr21054]

From memory I didn’t see any mixture screws.
No L or H

Diaphragms there was only 1 & it was fine.
Carb cleaner through all the holes / ports.

I’ve ordered another carb & plug

 

[Murdochcat]

Petrol & oil mix.
Plug seems ok but maybe dry

Put the lubricating oil for the chain in the petrol tank ?

 

[ipbr21054]

Ha ha I’m not stupid.
Two stroke oil & fuel.

 

[Murdochcat]

Ha ha I’m not stupid.
Two stroke oil & fuel.

Many chainsaw users have put the lubricating oil in the fuel tank and vice versa

One thing for sure is that the chance of starting it with this in its tank are almost zero

 

[ipbr21054]

Well then they are all stupid.

 

[Burnerman]

I remember now......no H and L screws, just one chrome idle speed screw on the side.
There are two diaphragms and gaskets, one top, one at the bottom, metering and pump.
If you want to open it up again, check the very fine gauze filter that is on the opposite side to the needle valve.
replacement carbs are readily available for less than £20 - I'd certainly go for one.
John

 

[ipbr21054]

Here’s the carb Ive ordered & looks the same as mine

Is the tick over screw your mention the one arrowed.