1989 Yamaha 225hp extremely bad spark

Ricky_rich

Petty Officer 2nd Class
Joined
Mar 4, 2014
Messages
125
I recently bought this engine. It has been sitting on a boat at the previous owner’s backyard for maybe 10 years and not used. And of course I can not start it. Have new plugs but almost no spark on them. Have only seen a very week (almost invincible) spark on two of the six cylinders.

There is no real speed on the starter, even with all plugs removed I think it’s slow. Can it be that since the engine turns slow the trigger coils don’t produce the pulse needed? Just an idea, I’m not really sure about how Micro-computer ignition system works.

Where do I start you think?
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,004
testing should be done.
measuring the peak voltages into and out of the CDI to see if they are in spec
 

Ricky_rich

Petty Officer 2nd Class
Joined
Mar 4, 2014
Messages
125
testing should be done.
measuring the peak voltages into and out of the CDI to see if they are in spec
I have 12v in on red wire to cdi when I crank the engine. But I understand that it's alot more to it. Can you tell me more about what to measure?
 

boscoe99

Lieutenant Commander
Joined
Aug 22, 2013
Messages
1,903
What is the complete model of the motor?"

They are not all the same.
 

boscoe99

Lieutenant Commander
Joined
Aug 22, 2013
Messages
1,903
Other than cranking the motor, what does battery voltage have to do with spark?
 

Ricky_rich

Petty Officer 2nd Class
Joined
Mar 4, 2014
Messages
125
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