Tohatsu Ignition Help M9.9B2 2 stroke

[w2much]

I went for a spin with this motor a few months ago. Owner said it had a mid speed stutter but would get over it and run fine. It would start and idle fine and after the stutter at mid speed it would open up and run well.He said he had soaked the carbs real well and the miss was still there.So I am finally getting to work with it. I find a weak spark. It will start run for quite a while then die. Sometimes when I go to start it it will sputter then die right away and there will be no spark. It has a newer CDI pack dated 2015.
I did some resistance test on the alternater coil (should be between 186 and 252) , it registered 296.
The exciter coil test showed no continuity as it should.
The trigger coil should read between 30 and 46, mine is at 63.
I also have a year 2000 Tohatsu 9.8 2 stroke with a different CDI pack and ignition configuration. It has the CDI with the coil built into it. Only three wires coming out of it, brown ,green and black. Green wire from the exciter, no trigger and obviously no blue trigger wire.
I took the newer pack hooked the ground wire to a good ground then the green wire to the red wire of the exciter, brown to the stop safety switch and ground to ground. I ran out of time to go any further but curiosity got to me and I pulled the manual starter. It has great spark. Tomorrow I will mess with it again. Can this configuration work. I do not see how it can work without a trigger but I cant see how a lot of things..Really just trying to save some money. I have four of these engines to pick from.

 

[pvanv]

CDI-fired outboards traditionally had an exciter to charge the CD and trigger to time the spark. Some models do that with one input coil (exciter only). Some newer smaller models (3.5, for example) have an integrated ignitor, without any external input coils. Issue is whether your exciter will fire the CD at the correct time. The old B2 is ancient, and Tohatsu has few or no parts. CDI electronics might have something. YMMV.

 

[w2much]

I was hoping to hear from you in particular. Thank you . I figured the timing would be the issue as there is spark. If the original exciter does not work I will switch it with the exciter that came from the parts motor which the newer CDI came off. I will post the results.

 

[w2much]

Well, it started but ran badly. I need to check the timing before messing any more.It started ran badly, I remembered that I had not tightened the flywheel. Is there, or where is the timing mark on the block or where ever. The flywheel is marked. Or should I just find the tdc with a depth meter or whatever it is called?.( have the tool but forget the name)

 

[pvanv]

The seam where the two block halves come together is the timing mark.

 

[w2much]

Throttle fuel pump or shift lever side ? Thanks

 

[pvanv]

Shifter side. You can use an induction timing light.

 

[Sea Rider]

Just stand right at midle of both mating surfaces, throttle grip fully till stops, check that the middle seam formed between both mating surfaces matches in straight line whatever timing vertical mark needs to be adjusted at. When correctly set, carb must open fully, re adjust individually timing advance, carb or both if are out of factory adjustments.

To check carb and timing advance synch check tiller side..

Happy Boating

 

[pvanv]

Just stand right at midle of both mating surfaces, throttle grip fully till stops, check that the middle seam formed between both mating surfaces matches in straight line whatever timing vertical mark needs to be adjusted at. When correctly set, carb must open fully, re adjust individually timing advance, carb or both if are out of factory adjustments.

To check carb and timing advance synch check tiller side..

Happy Boating

No Luis; He's installing a different CD, that does not have a trigger. So the ignition does not necessarily fire at the normal time, so the linkage settings don't apply. It likely won't work well, but we will see.

 

[Sea Rider]

Gee, I flew over the cuckoo's nest on this one. LOL!! Was thinking in terms of the newer 2 strokes M9.9D2 model and that's a M9.9B2 oldie...

Just to know. Besides having different electrical components there's a physical carb and timing plate synch, right ? Does this oldie employs a carb cam and time advance restriction as the 9.9 D2 model ?

Happy Boating

 

[w2much]

I tried a few combinations. I tried to switch ignition plates.I had hoped I could use the integrated exciter from the newer model on the olDr model. The screw holes did not match. I do not think it can be done due to the timing issue.
Just a thought but if two engines have the same stroke and bore, same Hp, then theoretically can their ignitions be interchanged as they would both be tdc at the same time. That is of course if parts could be fitted.

 

[pvanv]

Yes, BUT. You need to time the CD. That may be an issue, as you are finding. YMMV (your mileage may vary).

 

[pvanv]

Gee, I flew over the cuckoo's nest on this one. LOL!! Was thinking in terms of the newer 2 strokes M9.9D2 model and that's a M9.9B2 oldie...

Just to know. Besides having different electrical components there's a physical carb and timing plate synch, right ? Does this oldie employs a carb cam and time advance restriction as the 9.9 D2 model ?

Happy Boating

No, Luis, the ignition is divorced from the throttle. Advance is done internal to the CD.