Why will my motor always start at night?

cropduster21

Cadet
Joined
Oct 13, 2008
Messages
24
Ive got this 95 evinrude 15 hp 4 stroke. This has the power pack with the sensor built in and mounts below the flywheel

It has developed a problem of not getting spark all the time. Ive been running tests on the various components to try and isolate the cause for the past week. I seem to be getting current from the stator coil under the flywheel but Im not sure whats going on after that. I thought I solved this problem the other day when I found that the connector going to the power pak seemed to have pins that were not makeing good contact with the terminal pins on the power pack. I gently tweaked them a bit with some of my electronic needle nose pliers. All worked great for a couple days......Today I mount the motor on the boat and install a new ignition coil and give a couple yanks on the cord. It wouldnt start. I pulled the plugs and check for spark with my spark tester .............no spark!....... then tonight I check it again and it once again has good 3/8" spark.......... This is the 4th night I have observed this.......... I dont get it.. Its cooler at niight..... its darker at night.......... what am I missing here? anybody ever have a power pack act like this? Ive heard of coils going out when warm but not a powerpack.... by the way I ran this motor a good 5 minutes Thursday to see if the heat of the motor would make it quit......... it ran like a top!
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: Why will my motor always start at night?

Try heating the PP with a heat gun or hair dryer, and yes some PP failures occur when heated. If you use a heat gun, don't get too carried away with the heat.
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: Why will my motor always start at night?

Spark is weak all the time.
AT night you can see it, in sunlight you cannot.
 

cropduster21

Cadet
Joined
Oct 13, 2008
Messages
24
Re: Why will my motor always start at night?

Thank you for your suggestion of using the hair dryer. I took the hair dryer outside last night to try to see if I could get the PP to fail by heating it. I heated the pp for a few minutes while cranking there was a nice spark and then all of a sudden it went to no spark! I let it cool and spark again started while cranking. I tried the hair dryer again and was unable to get the PP to fail Sooo 50% failure rate is sure pointing toward the power pack failing as it heats up during the day........ Will try again tonight.

I have been able to see this spark in daylight. It is sparking great this morning at 8 am and its cool sunny and bright!
thanks for youre help!
 
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