Stihl 090 Early Conrod Problems

[ozziechainsaw]

I just emailed them again. I even gave them the OEM part numbers for both the Piston and the Rings.

Fingers crossed they contact me.

 

[89HD]

I might be able to help with that, sent you a message.

 

[ozziechainsaw]

Hi Guys,

Well I spent several weeks trying to find either a Geunine or a Meteor piston 66mm for the 090 but I just couldn't get one. I even emailed Meteor directly in the US. So I decided to buy just a normal cheap aftermarket piston.
The one I purchased is a West branded piston from a supplier here in Australia. It arrived in early January.

And I am not sure if anyone has had this feeling, but i just couldn't bring myself to fitting that type of piston to the 090. Everything in my mind was saying NO. If it wasn't this type/size of chainsaw I might have just used the aftermarket piston.

So after careful looking I decided to use the original piston. There were some very small mark on the skirt of the original piston, and even with my finger nail I could feel them. I also used a brand new set of 66mm Stihl OEM rings, Stihl OEM Conrod big and little end bearings. Plus I rebult the carby as well.

It all went back together perfectly.

However now I do not have spark, it did have spark before the conrod bolt broke. It does have spark sometimes when turning it over but it looks weak.

I will remove the flywheel and just check everything , but my big question is how do I remove the starter cup from the flywheel. I have tried to look it up and I really couldn't find anyting helpful . I even looked and the workshop manual and that wasn't much help either.

Can anyone help. I do not want to force anything .

Cheers

Justin

 

[cbfarmall]

Probably just super duper snug on the crank threads. Try tapping it or twisting it lightly.

I know exactly what you mean with the piston. Big, expensive saw like that needs factory parts.

Chris B.

 

[Bob Hedgecutter]

Hi Guys,

Well I spent several weeks trying to find either a Geunine or a Meteor piston 66mm for the 090 but I just couldn't get one. I even emailed Meteor directly in the US. So I decided to buy just a normal cheap aftermarket piston.
The one I purchased is a West branded piston from a supplier here in Australia. It arrived in early January.

And I am not sure if anyone has had this feeling, but i just couldn't bring myself to fitting that type of piston to the 090. Everything in my mind was saying NO. If it wasn't this type/size of chainsaw I might have just used the aftermarket piston.

So after careful looking I decided to use the original piston. There were some very small mark on the skirt of the original piston, and even with my finger nail I could feel them. I also used a brand new set of 66mm Stihl OEM rings, Stihl OEM Conrod big and little end bearings. Plus I rebult the carby as well.

It all went back together perfectly.

However now I do not have spark, it did have spark before the conrod bolt broke. It does have spark sometimes when turning it over but it looks weak.

I will remove the flywheel and just check everything , but my big question is how do I remove the starter cup from the flywheel. I have tried to look it up and I really couldn't find anyting helpful . I even looked and the workshop manual and that wasn't much help either.

Can anyone help. I do not want to force anything .

Cheers

Justin

Unthread it. Use something like a strap wrench, or oil filter wrench (small) with some old inner tube or something to protect the cup.
Once initial seal is broken and undone a couple of threads you should be able to remove it by hand.

 

[ozziechainsaw]

Thanks guys for that information.

There was no where in the workshop manual to say it was threaded. I have a strap wrench so I will use that and see how it goes.

Cheers

Justin

 

[Vintage Engine Repairs]

It might get a bit pricey, I spent $500.+ on a set after getting my first 090 and the Aussies always tell me chainsaw parts are twice that over there. I went a bit overboard and bought spare clutches cranks and bearings for a saw that sees very little use but I have them if ever needed.

Here here …me to

 

[ozziechainsaw]

Probably just super duper snug on the crank threads. Try tapping it or twisting it lightly.

I know exactly what you mean with the piston. Big, expensive saw like that needs factory parts.

Chris B.

Hi Chris,

If available and economical I will always use OEM parts, but there is definitely a time and place for quality aftermarket chainsaw parts.

I have another 090 and a Contra to do next. Hopefully the pistons are ok in them as well or I might just have to use the aftermarket WEST piston as I cannot find a 66mm Meteor or Stihl piston anywhere.

Cheers

Justin

 

[Bob Hedgecutter]

Thanks guys for that information.

There was no where in the workshop manual to say it was threaded. I have a strap wrench so I will use that and see how it goes.

Cheers

Justin

They are not threaded- just seem that they are that tight and over time and use- they can "flare" a bit on the shaft and become a tiny bit smaller than the threads above them- so you screw them off rather than pull them straight off.
I have the service manuals here somewhere- will have a look at what they say.

EDIT- they say this-

 

[cbfarmall]

Here's a picture of the underside of that starter cup.