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Terry Coombs[_2_]

Larry Jaques wrote:
On Tue, 11 Mar 2014 09:44:43 -0700, wrote:

On Sun, 9 Mar 2014 22:41:14 -0500, "Terry Coombs"
wrote:

OK , so here's what I got . I have an older 18" Poulan Wild Thing
chainsaw . It has an angle plate between the carb and cylinder ,
it's apparent purpose is to angle the carb up slightly . Problem
area is where the plate bolts to the cylinder . I can't keep the
damn screws tight , and when they loosen the saw just doesn't run
because it's a massive vacuum leak . I've tried red loctite , tried
dry , and they just keep getting loose . Carb to plate screws are
fine , no problems there . Fortunately I have 2 other FREE !
saws , so I can still cut firewood , but I'd like to get this one
reliable , as it has the longest bar . Cuttin' fool when it runs
right , as are the others since I learned how to sharpen chains .
Very important tool if you heat with wood !
I'm surprised that you are having the screws come loose even though
you are using Loctite. I have never had a bolt or screw loosen when
using Loctite properly. Are you sure that the screw and tapped hole
were totally free from any oil? The regular red Loctite will
withstand 400 degrees F without loosening and I would be surprised
if that area of the cylinder gets that hot. But it may indeed get
that hot. I have used locking Heli-Coil inserts where Loctite was
not appropriate. They will not let the screw come loose from
vibration, in my experience.

Eric, you're used to straight screw on flat surfaces. This is a case
of a screw head contacting an angled surface. Ideally, they should
have counterbored the carb flange at a flat angle to the head, but it
sounds as if they didn't.

Nope , it's properly counterbored . Someone upthread I think nailed it ,
it's a combination of differential expansion and vibrations . I'm thinking
I'll use some antiseize on the threads , then use green wicking loctite to
lock the bolt head to the flange of the angle plate - these are like #8 or10
screws with a torx head , no room to drill and lockwire . This has been a
pretty good saw , had it for several yeatrs . But it apparently wasn't
intended for heavy usage like I've been using it . That's OK though , I'll
get it repaired and hold it as a backup .
--
Snag