Recently I found my throttle cables were not operating in unison so purchased a
set of new throttle cables from Europa. On fitting the cables I found that the
cables operated acceptably on applying power but on reducing power the movement
was somewhat notchy and I was unable to make small reductions in power smoothly.
For me this was not acceptable. I tried reducing the size of the nylon
washers but to no avail. I tried changing the carb springs to a less powerful
version, no joy. Various routings of the cable made no improvement.
As I am the second owner of my aircraft I noticed the original builder had used
short cables with no real bends in the cables and smaller than plan nylon
washers
and so suspected he had suffered similar problems. Accordingly I elected
to shorten the long new cables believing the considerable length of the new
cables
may be producing too much friction to allow a smooth throttle operation.
So all parts removed and the cables shortened in an effort to reduce the
friction.
Refit and still no joy !!!!!!
I was becoming pretty irked. Thinking I may have received a one in a million set
of duff cables I ordered another set of cables from Europa. This is the point
where I began to think outside of the box, no pun intended (Throttle Box).
I connected one of the new cables to a carburettor in a straight line with no
throttle
box connected and no bends then I physically pulled the inner cable through
the outer. I found on pulling against the throttle spring, i.e. reducing
power the action was notchy and by no means smooth. This eliminated the washer
system being the problem. It could only be the inner cables rubbing on the
outers.
Bingo.
I carried out some research which resulted in my sourcing two 1.5m lengths of
TEFLON
lined outer cable. I was able to remove the inner cable ends from the shortened
inner cables and fit them to some new inner cable. They were removed by
heating and pulling them out with pliers and drilling the remaining cable out.
When operating the throttle I also noticed inside the throttle box the metal
washers
on either side of the nylon washers were rotating. To stop this I braised
one of the metal washers to the nut securing the spacer and braised the other
metal washer to the torque nut. I also fitted new nylon to plan sized washers.
This worked well and stopped everything rotating.
Once assembled the throttle action worked smoothly with no notchy movement on
reduction
of power. Also as the cables were moving in unison very smoothly carb
balancing was made easy.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483213#483213
|