A lot of ultralight pilots are getting ready to bring their craft out of winter storage,
and there are a few things they should do before they take to the air.
Like anything else in life, preventative maintenance, is just what it implies. If you do
this now, then that certain something shouldn't happen later.
With that in mind lets just go over your craft from top to bottom on a general basis to
see if we can identify some of the things your preventative maintenance program should
When you stored your craft you should have taken the breather and prop off, and with a
squirt bottle, with a very rich oil to gas mixture in it, (say 10 t0 1) should have revved
the engine up, and squirted the oil rich fuel into the carburetor, until the engine quit,
and or you couldn't breath anymore.
You should have then removed your spark plugs, lowered the pistons a little, and put a few
drops of oil down the spark plug holes, and then reinstalled the plug, and air cleaner.
Your next step would have been to drain the fuel from the float bowl, drain all your fuel
lines, and then your tank.
Having done all that, it now means that all you have to do is your spring
start-up maintenance schedule. (After all the other was your winter maintenance schedule).
Starting again with your engine, install a new set of plugs, properly gaped. Install a new
fuel filter, and if necessary after inspection, new gas line, and or vacuums line. (If the
gas line is hard, cracked, or discoloured it is generally an indication that it needs to be
replaced). When installing vacuum line make sure that it is NOT gas line, vacuum line used
to run the fuel pump has a much thinker wall thickness, and is generally a pink colour.
Make sure that the clamps that your are using do not cut into the gas/vacuum line, small
tie raps work well, as do small clamps available from most snowmobile dealers.
Check to make sure your low speed, and high speed jets are clean and clear of any oil
residue, and that they are the proper size. Check to make sure that your needle clip and
needle, in the slide in your carburetor are not showing any signs of wear, or loss of
tension. When reinstalling make sure that the needle and clip are below the steel
retaining ring on the Mikuni carb, and below the plastic retaining guide on the Bing carb.
Check your rubber intake manifold for cracks or tears, especially under your clamps on the
Cayuna manifold, and on the 65 hp Rotax manifold.
Check and lubricate your throttle cable, make sure that it returns freely to the idle
position, and that the cable isn't kinked or bent. Also check the little locking nut on
top of the carb body, where the cable enters, to make sure that it is tight to prevent it
from vibrating, loose.
If your craft has been stored in a barn or somewhere where mice can get at it, it is
suggested that you remove the top cylinder shrouds to check for any nests.
At the same time check your fan belt, for condition and tension. Check your recoil rope,
pulleys, and recoil spring tension, more than one pilot has gone out for his first flight
only to have the recoil rope and handle venture into his prop.
You have by this time had your airfilter off several times make sure that its clamp is
tight and that it is somehow safety wired to the carb body.
Check your belts on your belt drive for tension and wear. On the Rotax drive check to make
sure that the bolts holding the adapter plate are secure, the gears in good shape, and
that the oil slinger hasn't broken off.
It is also a good time to drain the oil in the drive an reinstall new oil. The correct
level is when oil starts to drip out of the bottom level hole on the side of the reduction
drive, and the correct weight of oil is 90 sae.
Check the bolts, and threads on the reduction drive prop flange. Many bolts become
stripped because of removal and reinstallation.
Check the prop for any nicks, dings, or abrasions. And repair or replace when necessary.
Also balance your prop.
Check the air pressure in your tires, generally they will go down after long periods of
sitting idle. When filling don't over pressurize as this could cause splitting of the rim.
Lubricate all cables, fittings, hinges, or moving parts that require lubrication, and
check for stiffness, signs of rust, or seizure.
Now fill your tank up with premium unleaded fuel, with octane boost, and a good quality of
oil. Check your engine for spark. If using a cylinder temp gauge remove the ring from the
plug, as the sending unit takes its place.
If you've got spark, reinstall the plugs, make sure the throttle is at idle, turn the
ignition on, put the choke on, and pull three times.
The engine should start. Remember the choke system on a Bing or Mikuni DOES NOT WORK IF
THE THROTTLE IS ABOVE AN IDLE.