Low spark on 2003 25hp

[barrie ontario]

Is there a way to test CDI , it just died and I get low spark ?
Any idea
Thank you

 

[racerone]

Electric start ?-----How are you testing spark?------Or does spark not jump a gap of 5/16" on a test device ?

 

[99yam40]

do you any idea what motor you are talking about?
We sure don't.
Make and model info helps a lot.

but with that said
yes you can test the peak voltage inputs to and out puts of the CDI, and compare them to the specs in your service manual for that motor.
it has procedures and specs

 

[barrie ontario]

Ok sorry it’s a Yamaha 25MLHB
First I just used the spark plug on head I never tried a 5/16 gap on a tester but I do have one to try ,
Second comment reply Thank you
I don’t have a service manual I’ll need to source info on
I don’t have access to the motor now it’s up north at cottage but I’m thinking spring lol
Thanks for the replies and advice

 

[barrie ontario]

Ok sorry it’s a Yamaha 25MLHB
First I just used the spark plug on head I never tried a 5/16 gap on a tester but I do have one to try ,
Second comment reply Thank you
I don’t have a service manual I’ll need to source info on
I don’t have access to the motor now it’s up north at cottage but I’m thinking spring lol
Thanks for the replies and advice

Oh yes no electric start

 

[racerone]

It is difficult to determine spark quality by using the plugs,-----Harder yet in broad daylight.

 

[barrie ontario]

Ok thanks so I will set gap to 5/16 and do it after dark .
I did see faint spark not as much as I see on other gas engines so I was thinking CDI so thankfully I must be wrong
Thanks

 

[99yam40]

need to know what peak voltage is going into the CDI and back out.
special meter or regulare meter with a DVA adapter to take readings

 

[barrie ontario]

Yes my Alzheimer’s is getting the best of me . I bought a DVA adapter last time I posted n 2013 .
Now I just got to get the values to expect .
I thank you very much