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Dominick
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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how do i test the coil packs and brain box on a 25 hp mercury

Customer Question

how do i test the coil packs and brain box on a 25 hp mercury outboard engine
Submitted: 5 years ago.
Category: Boat
Expert:  Dominick replied 5 years ago.

Thank You for Your QuestionCustomer

 

There are tests for the ignition charge coils (Stator Coils), the Trigger coils, and ignition coils...but there is no tests for the Control module...How this works is, test the components that you can, and if they test good, change the Control module....

 

If you have no spark at all, it is not the ignition coils - Odds of both coils going out at the time are "NOT"...

 

Give me your Model and Serial number of the engine and I will look the tests up for you...

 

Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience: 25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
Dominick and 3 other Boat Specialists are ready to help you
Customer: replied 5 years ago.
dont know the model but the only serial # XXXXX can find is 0b224421
Expert:  Dominick replied 5 years ago.

 

The serial Number came up as a Belgium Engine (Weird, Unless Your In Belgium !!!)

 

The Model # XXXXX(NNN) NNN-NNNN- Ser# XXXXX - 25 HP Twin Cylinder Mercury / Mariner..

 

The parts below are -

 

All Tests are using a DVA (Direct Voltage Adapter) Type Meter With Sparkplugs Removed and Coils Attached to a Spark Board (Use The Sparkplugs Grounded to Block)

 

Stator/Charge Coil - #2 - 20V+ High Speed Coil / 180V+ Low Speed Coil

 

Sensor Coil - #7 - Same Test as Above - 5v Pulsing

 

Ignition Coils # XXXXX - 180V+ Pulsing From Control Module

 

Power Pack / Ignition Control Module - # XXXXX = PN#339-7452A3 No Longer Available From Mercury but is Available From CDI Electronics PN#(NNN) NNN-NNNN 3 For = $158.00

 

 

 

 

 

graphic

Customer: replied 5 years ago.
is there an ohm reading i can do on it and if so which wires read what
Expert:  Dominick replied 5 years ago.

Ohm reading on the Ignition Computer??? No....

 

Ohm readings on Coils is a haphazard way of testing, if it test bad it may not be, This is because the resistance will vary with temperature and age. I could not find the values for the coils, and I would not recommend this method of testing...We do see these resistance measurement for other models, but once again we don't recommend this type of testing....Either it will produce the required voltage or it won't, much better...The DVA volt meter is available from SIERRA Marine Supply and Cost about $65.00, less than a hour labor at the shop...

Customer: replied 5 years ago.
thanks
Expert:  Dominick replied 5 years ago.

Your very welcome, If you get a moment to FeedBack, I would apreciate it....

 

Thanks Again,

DominickB

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Dominick
Dominick
Marine Mechanic
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25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified