90TLRT Y.E.M.I.S. CDI CONTROL UNIT

[magillagorrila]

I have 1995 Yamaha 90 TLRT 2 stroke I have replaced all ignition components including cdi which was 517.00 still will not fire idle or over 1500 rpm on #2 cylinder I have performed all resistance tests and voltage tests have talked on line marine mechanics and local ones evert one is stumped fyi I am a retired marine mechanic never found a ignition I could not diagnose am I going nuts or what any suggestions would help at this point

 

[99yam40]

how many pulser coils does you motor have?

I think #1 & #3 fire is controlled by pulser coil and #2 is made up from crank position sensor and CDI

something to look into as I am not an expert on a 90

My C40 has 3 pulsers so it is easy to figure out

 

[magillagorrila]

I have replaced all pulsar ,coils , cdi stator and lighting coil assy. have tried even replacing ignition coils with some I know to be good new spark plugs the whole ignition system with the exception of the flywheel crankshaft sensor is low speed pulsar / trigger pulsar coil is under flywheel all have been replaced

 

[99yam40]

I would think it may not be under there.
you need to find out

Sounds like you have replaced things you have no idea what thay were and do not know how many pulser coils you motor has or is suppose to have.
service manuals help a lot if you get the one for your motor

 

[magillagorrila]

i have ran the tests with manual right there even the manual says components may pass these tests and be bad and try to duplicate conditions how if it does not run I did mention that I am a retired marine mechanic and have never had this problem with diagnostics and have even checked entire system including harness for shorts to ground

 

[99yam40]

So you have a service manual. Good to hear,
how many pulser coils does this motor have/use? specs sheet should tell you how many have specs
where is the crank position sensor
and does it test out OK
not just ohms, but peak voltages
also while cranking over the manual should give specs for peak voltages connected and unconnected (loaded/unloaded)

peak voltages need to be read with a special meter made to read these ignition systems, or a DVA adapter with regular DVM