I need some input on a 1991 Yamaha c115tlrp

kbrad

Cadet
Joined
Jul 29, 2011
Messages
8
Good Morning . Help needed . I have a 1991 Yamaha C115TLRP that has been a great engine for me and does always easily start cold or warm . When cold It will start fine but not fire on the number one cylinder . I will idle out to a close fishing spot and fish for 15 minutes or so , start back up and it will be fine for the rest of the day . The next day the same thing . It has been doing this for a good while now so time to do something . I have tested coils and swapped coils and still the same thing no fire on number one when cold . I have replaced plugs . I have run a jumper wire from number one connection on the CDI to the number one coil and same thing , no fire on number one . So, doesn't that rule out everything from plugs up to the CDI ? One other thing along this same timeline , the tachometer will occasionally jump to double rpm's and then back to correct rpm's . Even though it is still charging battery could this be the problem with the number one cylinder coil not firing ? Is there something else to look at here ? Any ideas ? Thanks
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,253
if there is no spark ,you need to measure the voltages into and out of the CDI
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,253
special test equipment is needed along with the specs in you service manual to compare the readings to
 
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