Aero Corsair Black Devil 172 Specifics
Notes and references to this specific engine.
There is a wealth of information on the U.S.
AeroCorsair.com. Links are listed here for convenience.
See also the Chapter 12 article on
Bearing Replacement |
Other articles specific to the Black Devil 172:
Black Devil Pull Starter Rebuild
My Black Devil 172 won't start and I'm in the
field. I Can't Start My Black Devil 172.
Assuming your wing is laid out and you've found
this on your smart phone. If you have a someone who can help, have them
brace the motor.
situation, where a motor is being recalcitrant, is among most likely
times to have it
surge to power and cut your arm off. Be careful! Be braced and be ready
on every pull!
1. Try starting it withOUT priming. It's
probably too late because you're reading this. But, in the future, do
this first. Take the spark plug out, if it's wet, dry it, then try
2. Prime. Make sure you see some fuel go into
the carb with no more than a few small air bubbles. Any air bubbles
indicate a problem but just a few shouldn't prevent it from working.
3. After priming, try holding some throttle in
a way that will *NOT* increase throttle if the motor goes to power. It's
still dangerous and, if you have to start it with the throttle open, the
motor needs work.
4. Let it sit. After priming, the motor
frequently is easier to start after it sits for 2 minutes, possibly
because the fuel vaporizes and is easier to ignite.
5. If you have the manual decompressor, try
*NOT* using it (if you can pull against the compression). This will be
hard if the compression is really good and it will always be harder on
your pull starter.
Spark Plug Selection
Thanks Dave Moore and Brian Del Campo with this information.
The NGK BR9ES works but numerous pilots have found the following spark plugs to improve starting
characteristics of the Black Devil motor.
Namely, it may allow starting if it gets flooded. These
are both resister plugs which reduces radio problems.
- Denso W27ESR-U, recommended by the motor's importer, Alex Varv.
- Denso W24ESR-U, a hotter plug that was the one cross referenced to
- The "U" designation mean it employs their special U groove that is
what helps starting when the motor is flooded. It is less likely to foul
even if you overprime.
- Both plugs are available at Autozone.
Two bearings go on large pulley. You don't want to do this operation
often, so get good bearings. #6004 c3 bearings are recommended. Here are
two that work according to Alex Varv, the U.S. Importer. They carry the SKF sealed bearing. You want . Whatever you get, the numbers should have
an s on them to indicate that they're sealed.
- SKF 6004 2RSJEM. These are available from Motion Industries,
formerly many outlets were called Berry Bearing. Motion Industries does
not, as of Sept, 2007
- NSK 6004DDUCM.
Most Black Devils come with a Walbro WB37c carburetor. The membrane
kit is D10-WB and you can buy the springs and other
replacement parts for the carb here.
MojosGear sells the complete carb
which is great to have on hand. If you ever suspect carb problems, just
swap them out. If the problem goes away, enjoy flying that day and
rebuild the old carb when time permits. Then reinstall it to make sure
the problem does not return and you now are back to having two airworthy
When installing the kit, there
are two identical membranes that come with it. Use the light colored
Reduction Drive & Belts
For example, he found Jason belts for the Black Devil (and they
only cost $11.00 vs. $48.00 from the manufacturer). That motor is now using
Opti-belts which can be had for $13.00 each. At least one pilot is
using a Goodyear belt which seems to work fine and is under $20.00
The automatic valve that comes with the motor is prone to sticking in
the open position. If that happens the motor will be extremely difficult
to start. It must be cleaned frequently with carb cleaner or gasoline,
maybe every 10 hours. A solution is to install a manual button
decompressor. You press the button to open the valve for starting. When
the engine fires it closes, popping the button out. To restart, you
press the button again. You won't be able to reach it in flight so
airborne restarts will be difficult at best.
The correct valve is
available from Alex Varv. Another valve that works is available from
http://www.arvadarentalls.com/ as of Apr 14, 2008. Ask for the
manual decompressor. It's not quite tall enough to reach as easy as OEM
but does work.
Be careful removing the automatic valve, the small hex
ring on the nipple wasn't designed to torque the whole valve out. You
must have a real thin walled socket to get it out. Alex sells a special
tool that comes in handy for the purpose. You can also grind down a
regular socket but that takes a lot of grinding.