Posted by ron barr (rwhb@…>)
OK here’s a mildly dumb question….can anyone
write a short description of how CVI ignition works on outboards? I tried to
find a link on line and having grown up in the days of SU carbs etc haven’t
had time to pay much attention to engines since- and anyway when I open the
hood/bonnet to my car all I can see is hose!!
Thanks
Ron
Hoyt F32
Newport RI
Posted by George Huffman (thatboatguy2@…>)
Hi Ron,I think you mean CDI? This stands for Capacitive Discharge Ignition. It’s used on many outboards (and many other applications such as many motorcycles) dating back to the 1970s. Here is a good description. CDI overview Hope this helps. George— In FreedomOwnersGroup@yahoogroups.com, “ron barr” <rwhb@…> wrote:>> OK here’s a mildly dumb question…can anyone write a short description of> how CVI ignition works on outboards? I tried to find a link on line and> having grown up in the days of SU carbs etc haven’t had time to pay much> attention to engines since- and anyway when I open the hood/bonnet to my car> all I can see is hose!!> > > > Thanks> > > > Ron > > Hoyt F32> > Newport RI>
Posted by George Huffman (thatboatguy2@…>)
Hmmm,
I just re-read that site I gave you and it might not be enough of what
you are looking for.
Major components of a CDI ignition on a small outboard would be:
High voltage windings and magnet (creating a magneto with the flywheel)
Low voltage windings and magnet (creating another little magneto
that is used to triger the “powerpack” or “CDI Module”
CDI Module.
Coil
Spark plug.
Typically you have something in the neighborhood of 100 to 200 volts
coming off that magneto of a/c power going into the pack. Most of the
time you have around 5 to 15 volts for the trigger or perhaps less I’m
working from a rather faulty memory here.
There is a capacitor as well as some other electronics mostly dealing
with ignition timing in the pack. The capacitor stores the high
voltage from the mag and dumps it into the coil when triggered by that
low voltage mag. The coil is used essentially as a transformer to
bump the voltage up to a crazy high figure delivering a very high temp
spark.
So…
For trouble shooting of course always check to see if you are getting
spark first. You can do this with a comercially available spark
tester such as available from davis instruments or you can make one
with an old spark plug, some starboard a nail and an alligator clamp.
So let’s say “no spark”.
You can do some more trouble shooting to determine if the pack is good
or not by determining if it is getting what it needs. Check ground
first. Then check to see that the trigger voltage is coming in using
a volt meter. Next check that high voltage VERY CAREFULLY not making
yourself part of the circuit!
(if you want to test the voltages accurately against factory spec you
will need what is called a “peak volt meter” but you can often ball
park it with a normal volt meter to get a go/no go)
If the pack is grounded right and is getting high and low voltage then
move on to the coil. If the coil ohms out good on both primary and
secondary windings then you have determined that you have a bad CDI
module. Bad CDI module happens to be the number two failure mode (in
my unofficial survey) right behind poor ground.
OH! Almost forgot. A lot of power packs have a ground lead that
stops the ignition to turn the outboard off. Make sure that wire is
not grounded out when you are trying to run the motor. Usually this
wire goes to either an ignition switch or to a kill button with a
lanyard.
Hope this helps.
George
— In FreedomOwnersGroup@yahoogroups.com, “ron barr” <rwhb@…> wrote:
OK here’s a mildly dumb question…can anyone write a short
description of
how CVI ignition works on outboards? I tried to find a link on line and
having grown up in the days of SU carbs etc haven’t had time to pay much
attention to engines since- and anyway when I open the hood/bonnet
to my car
all I can see is hose!!Thanks
Ron
Hoyt F32
Newport RI
Posted by paulsebra (paulsebra@…>)
George Great synopsis,
Ron, you can do a lot of trouble shooting with a Good V-O-M, if you
do not have one, get a Good one ( Fluke or similar $80 - $100), I
find that working alone is easier if the leads have the alligator
clips and the unit will make a tone when the status changes …
Volts and Ohms are the key to a CDI … you should also invest in a
shop manual for your motor … it will have table of MAX and MIN
resistance levels for the components, also MAX and MIN voltage levels
at various components. If the components have gotten wet, resistence
goes up (corrosion)and voltage goes down … Most need 8 - 10 volts
to trigger ignition.
If your engine has a battery, then the troubles may be in the wiring
outside the motor. The last outboard that I rebuilt was a 1995 200hp
Johnson Sea Runner … it would not run smooth or strong … the
V-O-M showed 8 volts at the motor when not running … the
resistence was traced to the ignition key swith … new switch - 13
volts at the motor, ran like a champ …
Good Luck … get a manual, well worth the $30 - $40 dollars in
aggravation alone.
Paul