Chainsaw maintenance Lanarkshire

[spudulike]

Just pop off the flywheel and check it but it is probably OK. If you increase the distance of the coil from the flywheel, it will retard the ignition timing and help with severe kick when starting it. Try around 1.5 - 2 thicknesses of a typical business card but watch out - if you go too far, the spark may fail. Opening up the plug gap has a similar effect on ignition timing.

[Stevie777]

Yeah, but it's sheared, Right?

[Stevie777]

14 hours ago, spudulike said:

Just pop off the flywheel and check it but it is probably OK. If you increase the distance of the coil from the flywheel, it will retard the ignition timing and help with severe kick when starting it. Try around 1.5 - 2 thicknesses of a typical business card but watch out - if you go too far, the spark may fail. Opening up the plug gap has a similar effect on ignition timing.

I don't have a flywheel puller, and as I cant easily source parts for this machine I'm reluctant to start using a hammer on it. I'll wait until I can source a flywheel puller as I don't want to be putting her to work with a sheared key that cost around a quid to replace..

[openspaceman]

11 minutes ago, Stevie777 said:

Yeah, but it's sheared, Right?

I very much doubt it, the chances of the flywheel  being close enough to still run after it has sheared are minimal.  If the nut is tight and you can still see the key and it runs it ain't broke.

 

The key is not what holds the flywheel in position, it just locates it and it's the taper and nut that fixes it. This is why you can file some off the key to advance the ignition and it doesn't affect the hold.

[Stevie777]

The engine won't run if the flywheel has slipped.?

 

I'll try increasing the distance on the coil. one looks closer than the other anyway.

[spudulike]

If the flywheel has slipped very slightly then the saw will run but will be underpowered and may rumble a bit if the ignition is too advanced. I reckon your saw just has a slight bit too much ignition advance. New saws have coils that move the ignition timing around to make the saw easier to start and develop more power. Older ones had fixed ignition timing and would often rip the starter out of your hands if the starting method was a bit lethargic.

[Stevie777]

On 5/19/2018 at 17:15, peatff said:

It just looks like a proper separate Woodruff key to me not one cast into the flywheel with the groove in the crank.

yeah, easy enough fix if that's the problem. Waiting on a puller arriving and we'll take it from there.

[Stevie777]

OK, I pulled the flywheel. The key was fine. So here's where I am so far.

 

Pull rope replaced.

 

exhaust port and exhaust clear of carbon build up.

 

cylinder and piston smooth and clean.

 

pulls over easy with plug removed.

 

start stop switch replaced.

 

Coil working fine, Plenty of white spark. New plug.

Still hard as hell to pull over once it hits top dead centre even with the HT lead off the plug. way too much compression. Any new ideas guys.?

 

As you can see from the pics of the flywheel and crankcase, This saw was clean, Very little use whatsoever.

 

 

 

[spudulike]

Excess compression tends to be either fuel gathering in the lower crankcase due to a leaking needle valve or a build up of oil in the combustion chamber causing a very good deal between piston and cylinder.

Not too much else left! Some saws do just have good compression and can kick but are generally 70cc+ in size.

[Stevie777]

2 hours ago, spudulike said:

Excess compression tends to be either fuel gathering in the lower crankcase due to a leaking needle valve or a build up of oil in the combustion chamber causing a very good deal between piston and cylinder.

Not too much else left! Some saws do just have good compression and can kick but are generally 70cc+ in size.

You ain't gonna believe this. Watch out for my next thread on the saw... I'll title it either 'I'm a big girls Bottom,' or 'Simply Embarrassing'.