[T Dickson]

My 225 yamaha has intermittent spark to #5cylinder I have swapped coils wih no change . With the engine running I disconnected the coil positive bullit connector and slowly re-plugged it and get spark between the connector (not actually touching connectors) but loose spark as soon as the connecters make contact. The cylinder will fire when the engine is cold but loses spark after the engine warms up for a few minutes .I am leaning towards replaceing the CDI UNIT but without knowing for sure, its a rather large investment for a spare part (electrical parts are NO RETURN).If anyone has some expierience with this problem I would could you please reply .THANKS T Dickson

[matt2002]

Did you look for cracks in the plug wires insulation ?

[T Dickson]

no I did not check for cracks -thanks,but I did try 2 complete coils with no results

[rodbolt]

myself?
before buying a CDI oer anything else I would carefully study the ign system and how it works on a CCS controled V76 3.1L OX66 motor.
until 200 RPM or so #5 cylinder is cut out.
between 850 and 2000 #2 is also shut down
so carefully rethink the problem before buying anything

[T Dickson]

I have found a service manual and will be checking all the electrical values of all the components . Thanks to all for the help

[rodbolt]

so whats the running issue?
remember between 850 and 2000 #2 doesnt fire, until 2000 RPM # 5 doesnt fire in normal running conditions.
its how the CCS system is designed on non V-Max motors using the ccs system.
V max motors do not use CCS.

[T Dickson]

All of a sudden its consuming lots of oil and running rough and smoking excessively at idle( intermittently) also acceleration is slow . I have done a compression test and found 115lbs across all cylinders which is great .I have more tests to perform .