Well, I made it to the PO and picked up my "new" cover. It must have come off a returned saw because the previous owner had modified it slightly to line up to the mounting screw. Anyway, now the knob falls out of the hole, so you know that will disappear the first time I have to clean the filter on the work site. the saw it came from probably seized the first time out.
I had glued everything together about a week ago and left the saw on the shelf until the cover arrived so I put the cover on and cut six or seven cookies, 20" diameter.
you can see that it lines up with the air intake better now.
View attachment 349079
because of this, a 3.7 mm spacer I inserted between the carb and isolator. it isn't finished here, had to be cleaned up and two holes for the impulse line drilled. It seems to me that either the isolator is too short or the cylinder is machined incorrectly, causing the misalignment.
View attachment 349080
here is the filter top gasket
View attachment 349081
after cutting the cookies:
View attachment 349082
still a mess, you can see where it's entering:
View attachment 349083
I'm about to give up and either run over this thing with my truck or buy a complete air intake system for a redmax. don't know which would be dumber.