cdm"s

[jimcrain1966]

my 2001 merc 50 hp was running good then tuned off and wouldnt get spark anymore. turns out all 3 cdm's are bad. what would cause this?right before it happened, i had gas leak that sprayed out and up on port side, could have sprayed under flywheel.

 

[gm280]

Sorry to hear about your engine Jim. But I don't think the gas spraying into the flywheel is your problem. How did you determine that all three Capacitor Discharge Modules are bad?

 

[jimcrain1966]

followed manual said to test cdm, all three failed and dont get spark. trigger tested good

 

[jimcrain1966]

ok, i bought 3 new cdm's, all tested the same as the originals so chart in seloc manual might be wrong. tested trigger again disconnected wires, connected blk meter wire to black trigger wire and red meter wire to each of the other three wires one at a time while cranking, never went over .5 volts. chart says should be over 1 volt

 

[Alumarine]

Maybe this site can help. http://www.cdielectronics.com/support/

 

[gm280]

followed manual said to test cdm, all three failed and dont get spark. trigger tested good

Jim, in the future, before buying replacement parts, think about the possibilities of having three modules go bad at that exact same time. The statically probability of that happening is pretty remote. Now I could easily see that IF the input and output wires were charred or burnt open and such, but three total working modules quitting at the exact same time, is a stretch. I also suggest you buy the manufacturer's model, year and HP specific shop manual for your engine and forget about those after market manuals. They try to cover too many models and in doing so really don't cover your engine very well. Buy a shop manual and you will have the gossip for your engine for future needs. With all that said, have you located the real problem yet? And at least you now have good working new spares for those CDM if you ever need one... So really not money wasted... Tell us what you have tested since the new modules were installed and what were the results so we can assist you. JMHO!

 

[jimcrain1966]

tested for spark again no spark, tested trigger no resistance and under .5 volts when cranking,i have rev limiter and regulator how do i test?

 

[gm280]

tested for spark again no spark, tested trigger no resistance and under .5 volts when cranking,i have rev limiter and regulator how do i test?

Okay, have you tested to see if the exciter coil (stator) has any resistance to ground. You can do that by putting one meter lead on one of the wires coming out to the CDM modules (with them all disconnected of course) from the stator and the other meter lead on engine ground. All other leads should not be touching anything else at this time. Just hanging in mid air or taped over. You shouldn't read anything at all. It should be totally open. If you do read anything, your exciter coil (stator) could be the problem... If you can post your model number and serial number I can find better info on your setup. But the Mercury pages go by model and serial numbers instead of year and HP. Let us know the results...

 

[jimcrain1966]

50 elpto 327891

 

[gm280]

I have tried to look up your engine but the numbers you posted don't seem to fit their listings correctly. The have a prefix to their serial numbers. Like 0G290585 and number listings like that. You can go to this site and see what is listed; www dot boats dot net /parts (of course remove the dots and spaces as usual) and then follow for your engine and see the break down and part numbers. Maybe that will help if you can see the layout of the parts for your engine.

 

[jimcrain1966]

sorry forgot the OT327891, also i tested the stator resistance it was a=0.00, b=0.01 then keeps rising, c=O.L, d=O.L. all three had same readings

 

[jimcrain1966]

You didnt specify if i was to crank during test, so i didnt

 

[gm280]

You didnt specify if i was to crank during test, so i didnt

No, when doing a resistance test you don't want to be cranking at that time. Does this layout look like your engine?

 

[jimcrain1966]

Yes Sir, Looks exact, how were results from stator, didnt sound good

 

[gm280]

Yes Sir, Looks exact, how were results from stator, didnt sound good

Jim, lets not rule out the stator yet but what parts have you now changed? The fact that all three CDM stopped outputting voltage for the spark, it certain has to be something feeding all three CDM modules. So lets work that angle and see... There is a trigger to fire the CDMs and if that isn't triggering, nothing works... So tell me what parts you've changed and we will go from there. And is the kill switch at the helm in the run position? If it is flipped (as if the drive was thrown overboard) it will kill the spark instantly.

 

[jimcrain1966]

just replaced cdm's. kill switch is on back of remote by driver.if it kills spark will it stop starter from cranking because it cranks.yes its in run position.

 

[gm280]

just replaced cdm's. kill switch is on back of remote by driver.if it kills spark will it stop starter from cranking because it cranks.yes its in run position.

NO the kill switch only kills the spark, not the starter. So it will crank all day long, or until your battery drains. But the spark will not spark and so the engine will not crank and run. Have to traced the wires going to each of the CDM modules? If so where do they go to. The stator or to a switching unit?

 

[jimcrain1966]

looks like some go to trigger and some to stator. whats a switch box?

 

[jimcrain1966]

also, schematic looks like if i disconnect blk/yel wire from rev limiter and touch limiter side to grnd. it will bypass kill switch, sound right?

 

[jimcrain1966]

or it the opposite i just disconnect blk/yel wire and leave unconnected?since switch grnds motor to kill?