Chainsaw Repair

Hello everybody this is my first post.  The oiler on my 306a does not work.  The manual oiler works fine.  I took it apart and don't understand how the cam drive works.  I can't understand how it grips the shaft enough to turn the gear.  Any help is much appreciated.

First post here, but the small steel cam gets driven from the shaft by the
"crush" when you tighten the clutch assembly down against the cam, or in
other words it is stacked in there like a washer being pressed against the
crankshaft journal. 

What a great engineering design, with the brass gear reducer cammed in a
roughly a 19 to 1 ratio.  There are 19 teeth on the brass driver, and 20
teeth in the stator. Note that one of the gear tooth pockets on the outer
gear is always empty. The face of the brass driver gear has a short cam
cast into it too, that the cross piece button rides on.

One turn is made to stroke the plunger for every 19 rotations of the engine, or
about 5 short plunger strokes per second at 6000 RPM.  Looks like the designer
must have played with his kids Spirograph drawing set back in the 70's, if you
remember those.

Anyway, you probably have a quad ring rubber seal that is simply worn
out, it goes around the plunger pin that is actuated by the cross shaped
piece that is driven by the face of the brass gear.  You have to dig it out of
the bore with a dental pick, at least most of the time you do.

Me too, I scratched my head a long time looking at the first oiler I took apart.  No mention of how  it works in the
Service Manual either.

There is pair of check valves in that system, one right at the bar slot opening (which is fine as your manual oiler is working), and
then one at the top of the tank pick up tube.  I'm assuming that the oil finder/screen in the tank is not clogged with debris,
as again your manual oiler is working.

Thanks again hotshot,  as soon as the weather fairs up I'll take that thing apart and fix it.  I like the way it runs,  it seems torquey.  How does yours do 3000 fps?

Here is a picture of my 306A.