2007 9.9 Tohatsu/Mercury. No sparks.

James R

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Thought this was a Suzuki but I am told that it is a Tohatsu. Tried the Mercury Forum with no result. Perhaps this forum will work. I need the resistance numbers for the Coil, Stator coil and the trigger coil.
Can anyone help.
Thanks.
 

Sea Rider

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Exciter Coil : 168-252 Ohm
Pulser Coil : 30-46 Ohm
Ignition Coil Resistance : 0.2-0.3 Ohm

Aside the Ohm test need to troubleshoot all the electrical components with a DVA test while cranking or with motor running..

Happy Boating
 

James R

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Thanks Sea Rider.
I am assuming that the ignition coil test value is for the primary. Is there a reading for across the secondaries. I have a Suzuki manual which shows what looks like a similar twin ignition coil and has a measurement between the two secondaries. I can do a pull start DVA test, if my arm holds up. Do you have those readings.
 

pvanv

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Merc 9.9 4-stroke may actually be a Tohatsu 9.8. If so, secondary to ground on the ign coil will be almost infinite. Also if a Tohatsu 9.8, you can test the CD box too.
 

James R

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Thanks pvany. Assuming that it is the Tohatsu 9.8 is there a test procedure that I might use for the power pack.
 

Sea Rider

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Need to clarify which motor are we talking about. There's a great CC/HP difference compaing a 9.8 against a 9.9, both are different horses. The mentioned electrical parameters corresponds to a 2 stroke Tohatsu 9.9 model. Forgot to state the Ignition's Coil secundary reading which is : 4.1-6.1 Kh.

Electrical Components Outputs :
CD Unit Output (Cranking) 198-220 DVA
Exciter Coil Output (Cranking) 100DVA min
Pulser Coil Output (Cranking) 4.75-5.0 DVA
depending on model, not all 9.9 use Pulser Coils.


Don't troubleshoot with electrical components excerpted from other brands motors, doesn't matter if being same HP, each brand/HP has its unique electrical parameters..

Happy Boating
 

pvanv

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Thanks pvany. Assuming that it is the Tohatsu 9.8 is there a test procedure that I might use for the power pack.
Can you post a pic of the motor so we can identify it? The Factory service manual is available for the Tohatsu 9.8, and has full detail.
 

James R

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I greatly appreciate everyone's help on this problem. I used the specs provided but nothing seemed to tally. I pressed the issue of trying to find a manual for the 9.9 Merc and finally found one through a friend who is a Merc dealer. The manual is an official merc product, but in my opinion a very inadequate one. It shows only resistance checks, no voltage checks. The resistances in the manual do not match those provided here, which is not unexpected.
Proves the point about not cross matching.
Thanks again guys.
 

Sea Rider

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I greatly appreciate everyone's help on this problem. I used the specs The resistances in the manual do not match those provided here, which is not unexpected.
If so, then the Merc 9.9 it's not a Tohatsu rebadged version...

Happy Boating
 

pvanv

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If it's an 07 Merc 9.9, it's really a Tohatsu 9.8 with slightly different carb, and possibly slightly different shift coupled to throttle. What is the actual symptom? There is an exciter and pulser as well as a siamese ign coil. You can check the exciter and pulser for both DVA and ohms. There also ohm tests for the CD, but your analog ohm meter MUST be below 9v (3v is OK) or you may cook the CD. Tohatsu has a great Factory service manual for it, also available in Nissan version; same price:
Covers 8A3 & 9.8A3 4-stroke models
Part #: 003-21056-1
List Price (MSRP): $41.67
 
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