Wind Vane Governor

[2414Gingerboy]

Hi, I Have an old 08S, not run for years, I put in a carb kit, got it fired up.

But how the hell do you tune it, when the governor keeps kicking in, and richening it up.

Any tips much appreciated

[2414Gingerboy]

Bump.

Nobody ever tuned a governed saw.

[openspaceman]

Bump.

Nobody ever tuned a governed saw.

 

Never done one with a vane governor, either disconnect its linkage to the carb or restrict its airflow. I've only seen them on B&S powered mowers.

[GardenKit]

Like openspaceman, I have never done a saw with a windvane, so can only speak from general principles.

 

But, contrary to the original post, the governor does not constantly 'richen' up the mix. It simply regulates the throttle butterfly. As engine revs drop the governor spring becomes master over the vane and opens up the butterfly allowing more fuel/air mix in which increases revs until the windvane becomes master of the spring and closes the butterfly to slow it down a little and prevent over-revving.

 

So tuning a carb with a windvane probably needs the vane active rather than disconnected. Tuning to 'rich' will encourage the revs to drop but the governor will bring them back, and vice versa when tuning to 'weak'

 

Although you will not detect a change in engine speed, as you would with a modern ungoverned 2 stroke, you should easily detect a change in the smoothness of the engine note and aim for the ultimate smoothness when backing off from rich.

 

Unlike a modern saw you do not need to be trying to get it to fourstroke.

[peatff]

Try a stronger spring on the governor. As above they don't usually alter the mixture just the throttle opening. I've not seen one on a saw wither but plenty of 4 stroke lawnmowers. Is the saw flooding ?

[GardenKit]

Be carefully. A stronger spring will increase engine revs.

[amfell]

the windvane is connected to the choke shaft there is a bit of adjustment with putting the spring in different holes on the choke / governor lever

the governor system was used mainly on the TS350 to presumably prevent "overspeeding" the abrasive disc

 

the Max engine Rpm is 10,000 acording to the WSM but there is no mention of the theory of operation of the governor

[GardenKit]

the windvane is connected to the choke shaft there is a bit of adjustment with putting the spring in different holes on the choke / governor lever

the governor system was used mainly on the TS350 to presumably prevent "overspeeding" the abrasive disc

 

the Max engine Rpm is 10,000 acording to the WSM but there is no mention of the theory of operation of the governor

 

A great bit of information Amfell. I looks like this is a little different to a normal governor as it appears that it does indeed alter the mixture rather than the revs, just like the OP said in his first post and contra to my reply.

[2414Gingerboy]

But, contrary to the original post, the governor does not constantly 'richen' up the mix. It simply regulates the throttle butterfly. As engine revs drop the governor spring becomes master over the vane and opens up the butterfly allowing more fuel/air mix in which increases revs until the windvane becomes master of the spring and closes the butterfly to slow it down a little and prevent over-revving.

 

Yes I can confirm that the wind vane IS connected to the choke, and therefore does richen the mixture.

 

the windvane is connected to the choke shaft there is a bit of adjustment with putting the spring in different holes on the choke / governor lever

the governor system was used mainly on the TS350 to presumably prevent "overspeeding" the abrasive disc

 

Amfell, I believe that it is the same unit as on a disc cutter.

Still unsure of how to tune it though.

Thank's to all for your input.

Sorry, have not got my quote's in properly.