Cant kill the engine

[stenart1]

Hi
I have an tohatsu MFS 18B2 4 stroke 3vg - 2006
I cant get the key to kill the motor. Not even the stop switch on the remote control or on the motor will work . Prevoius owner seems to added a switch on the motor that works as a killer.
But of course I want to use the key switch to kill the Engine.

Looking at the wiring diagram at page 48
Brown cabel and the black cabel are used to stop the Engine by key or stop switch on the remote Control
Brown cabel goes to the cdi box and black goes to the ground on the motor
I have tested the Brown cabel to the contact that goes from the cdi box and forward to the remote control .and also the black cabel to the motor
They are not broken.

In neutral key position or key complete off I have a signal / Buzz on the brown cabel for on the multimeter ( cabel testing )
In neutral key position for the black cabel I have no signal
In complete off key position for the black cabel I?ve got a signal.
Does this seems correct?

If so what else can be the problem?
I?m so bad at this so hoping for some support.
Below is the manual, I have the diagram on page 48.

http://www.tohatsu.com/tech_info/own_man_pdfs/Toh_99B2_15B2_18B2_4str.pdf


Br
Stene

 

[pvanv]

If you manually ground brown, does the motor stop? If so, the problem is in your wiring... if not, the problem is in the CD.

 

[gm280]

Obviously this is your problem, but it seems rare that we see such a question on these forums. The usually question is, I can't start my engine. Interesting to see somebody ask how to stop their engine. Equally obvious is the fact that the proper ignition wires are not connected up correctly to short out the ignition.

 

[msaunoras]

A few years ago I had the same thing happen to my 2005 NSF18B2. After checking all the wiring I changed out the CD unit, didn't fix it. Wound up finding a loose ground connected to the engine on the top left I believe (10mm bolt head only 1/2 turn loose). The wiring diagram shows the brown wire that signals the CD to kill the engine but it doesn't explain how the CD does it.

 

[stenart1]

thanks for the replys.
To ground Brown did not fix it.

Also have Another problem that maybe could take me closer to the problem.
The motor dont load the battery at all
The Cables from the motor gives 17-18 v ( mesured them off battery
connected to the battery it wont load anything.
If battery is 12,5 v in resting mode. With motor on it will still be 12,5
I have an ampmeter it gives me 0,2 amp from the +cabel from the motor

I belived that it was the regulator/ rectifier. Tried to svap it but still same issue.
Question.
Could the cdibox also manage the loading of the battery?
Or is one problem totaly apart from the other.
Attachment is a Close up of the Schedule Picture from page 48 link in first post.

 

[pvanv]

Whip out your Factory service manual and a good analog ohm meter and test the CD to find out.

 

[Sea Rider]

Has nothing to do with CD runs on an independent alternator coil located under flywheel next to CD exciter coil. Both feeds both electrical components independently. Seems you'll need to change CD and rectifier at same time for engine to work well as expected.

Happy Boating

 

[stenart1]

Thanks for your replys
The service book is bought online now. I dont have an ide how to measure the box, but I?m gusseing there is a guide in the book.

Sea rider: the rectifier is brand new and did not fix the loading problem.
You think that cd box will solve both problem now or will the loading problem still be present with a new box?

 

[pvanv]

Two separate issues.

The CD won't operate properly if its black ground is not properly connected. Assuming it is properly grounded, then shorting the brown lead (coming from the CD) to ground is supposed to kill the ignition. If it doesn't, the CD has a problem. Your initial continuity test of the stop circuit at the RC box shows that it is working. What kind of "extra switch" did the original owner add, and how is it wired?

The white and yellow wires from the alternator coil (under the flywheel) feed AC to the rectifier/regulator, which converts it to DC. If the coil is bad, then the rectifier is not getting power to convert. If the diodes in the rectifier are bad, you will not convert the AC to DC.

The Factory (not aftermarket) service manula has full analog (not digital) ohm meter tests for those components.

 

[stenart1]

No Title

Hi Paul and thank you for your respond.
I have manually ground the Brown Cable from cd and motor still running.
The rectifier is brand new from US
Can i disconnect yellow and white Cable and mesure this while motor is running, if so what values do you expect me to find from alternator coil if it?s working.
I suspect that the book will not arrive for some day yet.

This is what previos owner did to kill the Engine.

 

[pvanv]

Yes, it would be possible. The Factory way is to use an analog ohm meter to check the coil.
The PO was grounding the wire from the cd to the coil. I am sure that would kill the ignition. Might not be healthy for the cd though.

 

[stenart1]

The book arrived today. Been checking some figures. 1 easy test to do were to disconnect yellow and white Cable from rectifier to alternator
but i did now see that I did mesure from ground to cabel. I should have measured cabel to cabel. :-(

I know you have written that I should use an analog ohm meter . But should?t a digital multimeter show the same figures?

 

[stenart1]

So white and yellow Cables fr?n alternator to rectrifier tells me
23,4 ohm 24,6 ohm

Book tells me that the resistance should be 0,27-0,41 ohm
First I tought that some decimal were off but it really says 23,4 ohm

I also mesured the AC from that Cables while enging were running
29-32v . Here I tought that it shold be + 100v?

Can my values be correct and the stator as you stated be the part that need to be switched

 

[pvanv]

Most digital meters do not provide the same level of drive to the circuit under test. Further, if the meter uses a battery with more than 3vdc, testing some CD units will damage them.
Inductors have a wide tolerance, often 50% in mhos, but dc resistance is pretty consistent. Yes, that alternator should be less than 1 ohm resistance, measured with an analog ohm meter. You can also test resistances of the rectifier, showing whether all 4 diodes are OK.
If you disconnect the battery,and test voltages both in and out of the rectifier/regulator, do you get reasonable values?

 

[stenart1]

Just amazing Paul
Your last post got me out again.
Tried again to measure alternator. Halted for a sec then I saw it. The Cable from rectrifier yellow , were contected with yellow red. Carbonator accordingl to the schema. Now i measured yellow and White. Don know if my poor skills or the heat is giving me odd numbers. but I got different readings, from 0,0-1,5. ohm
Volt is 14-16

The retricifier still same values.
I connected Everything again yellow to yellow. And of course it works.
I can measure 3-10 amp from motor to battery depending of rpm and also I now can see that the volt on the battery s raising..

I?m very sure that i did?t dissconnect the cords wrong, seems like Po or factory or shop did something wrong. Cause there is just no way that you discconect 2 yellow and a white cabel when you need 1 White and 1 yellow.

I tried to check if old rectrifier should work, but it does?t.


Now I only have my initial problem left.
Turn of the motor with the key.
I also agree that I should swap cdi box.
But it would be fun to measure this error in the box

My tester is an UNI-T 203
uses a 9 v battery
Ofcourse I dont want to damage cd box, do you think i?ll will do this when measuring?

 

[pvanv]

Dunno. Based in the other mis-wiring, I would verify each and every wire to be sure nothing else is mis-wired. Then, if grounding the brown from the cd does not kill ignition, you have a bad CD.

 

[stenart1]

I?v have now got my new cd. But it wont kill the Engine. I cant found out whats wrong or how to track this further. Any tips? I cant see anything loose at all ( ground )

 

[Sea Rider]

How that you have a new CD, what about the kill switch, if pressing it or removing safety lanyard from it does not kill the engine that's the culprit.

Happy Boating

 

[stenart1]

I tought the error were in the cd. So I ordered one pcs.. Money not so well spent :-(
No either key or removing safety lanyard on the remote Control or motor will kill the Engine.

 

[stenart1]

I have check loose bults I cant find anything. It seems like everything to the cd box is ok?