Stihl MS181, Hard to pull cord,wont start.

[bmp01]

Micky,

It probably would be quicker/easier to get some one to look at it for you.  But before you do a couple of quick things to put to bed:

-Post a picture of the piston as seen through the exhaust port (now you've got exhaust off).

-Really make sure you've got the chain brake disengaged. 

-Pull the clutch drum off  ( its the thing the drive sprocket is joined to,  held on with the 'E' clip) and the bearing inside. You need the chain brake disengaged to do this as the brake band will grip the outside of the clutch drum. Do NOT attempt start the saw like this (ignition off please while you pull the cord) we're just trying to find out if the clutch was making the saw hard to turn over. 

 

Maybe there will be a clue in here.

 

By the way, not every MS181 has the Stihl easy start mech,  but it's a small displacement saw that should pull over pretty easy anyway. 

 

bmp01

 

 

[EricBradley]

if it pulls over easy with no plug in as stated in first post and is hard to pull with the plug in its got to be compression related, it cant be anything else, sounds slightly like hydraulic lock.

[bmp01]

11 minutes ago, EricBradley said:

if it pulls over easy with no plug in as stated in first post and is hard to pull with the plug in its got to be compression related, it cant be anything else, sounds slightly like hydraulic lock.

If you read the first post through he says it was hard pull over and that's why he put some thin oil down the plug hole. .... it subsequently loosened up (or he just got used to pulling it over). 

 

Maybe the O.P. can confirm that's true AND if the brake was on or off and if the ignition module had been gapped correctly at that stage. 

Actually just take the 5odding ignition module off, take the clutch off, and show us a picture of the piston through the exhaust port.......

 

bmp01

 

Edited October 11, 2017 by bmp01

[spudulike]

You sure it isn't a 181SE - now they are a bit brutish to pull over.

A little girlie can pull these saws over, if it spins over with the plug out but not with it in then it has to be some sort of hydro lock in the bottom or top end of the saw unless the plug is too long....this could run and run

[bmp01]

37 minutes ago, spudulike said:

......this could run and run

It could. ...... but then again it might never,  ever ...... run again.....

 

I get the feeling is either goosed or something daft.  And before long it will be more economic to just swap the engine (and carb) for some aftermarket parts.

 

[spudulike]

Try taking the plug out, taking off the recoil (Starter) cover and turn the flywheel round slowly with your fingers and see if there are any tight spots. There will be some attraction between the magnets and the coil at top dead centre so expect that but it will be smooth.

 

If this is OK, Turn the saw upside down with the plug out and turn the engine over via fingers and flywheel and see if any liquid comes out of the sparkplug hole.

 

If it is still free, put the plug in but very loosely and turn it over the right way up using the same method and slowly. If it is OK then do the plug up and turn it over again. You should be able to turn the saw over very slowly even with the plug in and even a slight hydro lock will give if the rotation is slow enough.

 

See where this gets you.

[bmp01]

Just a thought on the hydraulic lock theory suggested here with loil below the piston - if the saw is held completely upside down, the piston will be like a cup holding on to the oil. To get that fluid out, place the saw on its side (either the chain side or the pull start side) and turn the engine over, this should allow the liquid to flow through the transfer ports to the top of the piston.  Then you can turn it upside down again and drain from the spark plug or if the exhaust is still off you can drain it from there.... 

 

 

 

 

[billpierce]

If the crank is full of oil will it not be jizzing out the impulse line?

[spudulike]

2 minutes ago, billpierce said:

If the crank is full of oil will it not be jizzing out the impulse line?

Nope as it will be connected to the carb. Quite like the idea of the piston cupping the oil/shyte though. I guess it may puddle there and then fall to the bottom of the case once righted and then it would blast up the transfers when pulled over and voila - hydro lock in the top end!

That is why I said turn it over slowly first to see if it would turn rather than giving it a full pull. The laying it on its side or standing it on its front so it runs out may work!

Funny that a 10 minute workshop job takes a week on here

 

[mickyblueeyes]

4 hours ago, peatff said:

If I were you I would get someone who knows what they are doing to take a look at it for you. Pouring petrol in every orifice isn't a recognised remedy for a stuck saw. You fitted a new ignition module, is it catching the flywheel  and is the ergo start working ? A six year old could pull my mate's MS181 over and if you are not sure where the clutch is are you confident to pull the top end off ? Watch a few youtubes and look online for similar problems then have a go at it.

At the moment getting someone else to look at it is not an option unfortunately as i am in between jobs at the moment and funds are low .Nothing wrong with the clutch on inspection so ruled that one out.It isn't the Ergo Start model ,Will look on youtube for some ideas.Cheers for reply.