sthill FS450 Vibration

[Richard 1234]

The engine is attached to the shaft properly isn't it?

I had the engine on an old fs85 come loose and that was vibrating until I realised it was that the bolt had worked its way loose and fallen out.

[GardenKit]

Check that both clutch shoes are free to rotate outwards. I have known them to stick (rust) between the side plates on some Stihl Brushcutters. That will throw it way out of balance.

[simonRribeiro]

Check that both clutch shoes are free to rotate outwards. I have known them to stick (rust) between the side plates on some Stihl Brushcutters. That will throw it way out of balance.

 

 

I will definitely check this ! there was a lot of rust coloured dust that I had previously assumed was just clutch dust. this is something I may have overlooked, I will report back

[GardenKit]

These pictures from my library may help.

 

The first one shows a siezed shoe, although in this case it was stuck out causing the head to constantly rotate as well as vibrate.

 

The shoe will be partly gripped by rust between the two thin plates and partly by a rusted pivot bush as shown in the second picture.

 

The cure is to clean off the rust, press the bush out (as in the picture) and clean it with emery, then grease it before pushing back in.

 

This is a fairly common problem with machines transported in open back pick ups.

 

[simonRribeiro]

ok, sorry for the delay, I had a chance to look it over today end the clutch seems fine, no rust and all parts move fine.

 

I am at a loss, looks like I must have a problem with the engine/crank but I just find it hard to understand.

[Stubby]

Are you running a metal blade ? If they are slightly bent they can go out of balance . Long shot I know .......