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1997 mercury 150 no spark

racingdave35

New member
Last Sunday boat ran perfect, on tues. went to take it out would not start at all at the ramp. Did diagnostic test with a volt meter, turns out the trigger was out of spec. on voltage, ohms were fine though. Ordered a new trigger, installed it, fired it up, primed it, choked it, hit the key and fired right up. But, tried it again 2 minutes later and nothing, checked for spark, and now there's no spark again. Is there something that could be killing $200 triggers? Or is the trigger fine, I'm just looking in the wrong place?
Dave
 
Check the stator is in working order.

Just replaced one of these last week, on a customers engine that had the same symptoms as you.
 
If you don't have a DVA equipped meter, or the adapter, forget about the voltage readings.

A regular multi-meter will NOT give you the correct voltage readings.
 
I have a pair of 1997 200 EFI's with one giving me trouble. Last year I chased my tail trying to find out why the engine lost most of its power and would not rev over 3500 rpm. I finaly determined it was the Trigger and replaced it. This past weekend the motor started doing the same $%^&* thing. I am about to start the troubleshooting process again but was curious if you had got to the bottom of your issue? I am wondering if I should be looking at the stator or switch boxes? I had to replace the voltage regulators last year prior to the trigger.
Thanks
 
Joe, the trigger is kinda isolated from the other igntion components - what I mean is, a bad regulator/rectifier can cause a power (back-up) that could toast the stator (or vice versa), but the trigger kinda does it's own job simply sending a pulse to the switchbox (or CDM's) when it wants the cylinder to fire.

That pulse simply tells the switch (SCR) in the switchbox/cdm to turn on to let the capacitor release the power it has stored - the SCR (silicon controlled relay) is, as the name states, a relay - so the power stored in the capacitor is never in the same circuit as the trigger itself (so even if defective the power can't feed backwards into the trigger and fry it).

Trigger issues are sometimes (most times) very difficult to isolate unless they quit altogether.

Frying a second trigger in a few months is quite unusual but could indicate a bad ground on the unit itself - or the first one just went from old age and the second was defective from factory...
 
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