power pack troubleshooting '94 90HP TLRS

waterbill

Petty Officer 2nd Class
Joined
Apr 4, 2003
Messages
106
The #2 cylinder was not firing. When plug wires were switched during a spark test, the #2 plug fired, and the one switched to did not. Next, I disconnected the wire sending power to the #2 coil and switched it with the wire sending power to the #1 coil. Again the #2 coil worked, sending a spark across the gap, but the #1 coil with the #2 input wire connected did not. This tells me that the #2 coil is not bad, but that the power pack output #2 is bad.
Here is my question: Should I go ahead and buy a new power pack? Is there anything which could go wrong with the pulser coil, charge coil or crankshaft position sensor that could cause the power pack to not fire #2 spark coil? Wouldn't that affect all three coils? The manual does not say anything about that. Also, I did perform an ohms test on the power pack input connectors, per the manual. What's really wierd is that all the readings are within specs. Maybe the #2 output wire is broken somewhere inside the pack. Who knows, anyone out there? Thank you.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,078
Re: power pack troubleshooting '94 90HP TLRS

follow the manuals steps for testing voltages into and out of the CDI, that should tell you where the problem is.
not sure on that 90 but it may have the #2 output generated by CDI not using pulser coil direct input
at least I believe I read that somewhere before
 
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waterbill

Petty Officer 2nd Class
Joined
Apr 4, 2003
Messages
106
Re: power pack troubleshooting '94 90HP TLRS

You are right. I just found in the manual where it says the single pulser coil in this engine fires cylinders 1 and 3. The YMIS microcomputer in the CDI unit fires Cyl. 2. A failure of the YMIS will extinguish the #2 spark. it says. Based on that info, do you think I should go ahead and spend the $580 on a new power pack? Or should I spend an additional hundred and fifty to take it to a mech with a peak reading voltmeter to check out the V in and V out?
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,078
Re: power pack troubleshooting '94 90HP TLRS

I would spend the money on a peak reading voltmeter or a DVA adapter and a regular voltmeter to take the readings.

Then you will have that equipment to use on other OB motor troubleshooting
 
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