cdm ignition system

[vettman]

Hey all; Of these three electronic componets, -- trigger, stator, cdm modules,-- can either or all function badly at idle, but preform well at higher rpm's ? I guess what i mean do these items either work or not work or can there be some in between ? Have rough idle but runs great over 2000 rpm. Carbs, fuel pump,fuel hoses ,filters,compression, link & sync, plugs, reeds all check out ok. Doesn't matter hot or cold. 2000 90 hp 3cyl. merc. 2 stroke. Thanks for any info.---- P. S. Are these 3 items prone to fail or pretty reliable?

 

[Faztbullet]

Re: cdm ignition system

can either or all function badly at idle, but preform well at higher rpm's ?

A bad CDM module can cause weird thing as all 3 are connected together thru the harness as with the stator as it could have low voltage to cdm modules. Better to go to CDI website and download troubleshooting manual and get a DVA to test beforethrowing parts at it.

 

[aussieflash]

Re: cdm ignition system

Did you do the checking or a mechanic?From what you say,I would double check for good spark,Reed valves and timing.

 

[vettman]

Re: cdm ignition system

Aussieflash. Mechanic did the above things . Top cyl. seems to be less responsive when plug wire is takin off while running, compared to the other two during same test. He did not do any other electical tests to motor . I may have to have that done . Where can i get a dva and will it test all three items i mentioned? i have the clymers manual . Will that get me by to do tests myself ? Thanks

 

[CharlieB]

Re: cdm ignition system

Check these links to see if your service manual is still available
http://forums.iboats.com/showthread.php?t=309079&p=2072211#post2072211

http://1manual.com/Mercury manuals/Service_Manual_Index.html

Read this thread on building your own DVA adaptor easily and cheaply.
http://forums.iboats.com/showthread.php?t=374544

 

[oldman570]

Re: cdm ignition system

CharlieB has it right on. At 1manual.com it gives all the test procedures for testing the ing. system for your motor. It also states " Intermittent, weak, or no spark at any one spark
plug usually indicates a bad SPARK PLUG,
COIL, or SWITCH BOX" . Sounds like a good place to start testing.
Oldman570

 

[vettman]

Re: cdm ignition system

Thanks all. I've got my homework cut out for me for a while . Will try all responses. Thanks again