Tohatsu M25C3 with no spark

[Johan Hansson]

Hello.
I have a Tohatsu M25C3 with no spark.

First i tried to change the ignition coil (3a0-06040-1), but still no spark.
Then i change the CDI box (3p0-06060-0), and still no spark...

(and changed the pluggs)

OK, so i measured the exciter coil (with the engine spinning) and got 104 volt AC, is that correct?
And when i measured for resistance, is seams the coil is broken (no ohm) is there a semi conductor in the coil?

Please help me out.

 

[pvanv]

Re: Tohatsu M25C3 with no spark

I would get a Factory service manual. Then you can troubleshoot with a plan. If you continue to just change out parts, you will eventually change the culprit bit, but it may end up being rather expensive.

Yes, 100v into the cdi should be adequate.

 

[Russ Drummond]

Re: Tohatsu M25C3 with no spark

Johan,

Any luck finding the source of your problem? I have the same issue with a Tohatso clone (i.e Mercury 30hp LW). No spark. Suggestion is that the CD unit is at fault. Replacement is VERY expensive and I am wondering if there are other things I should try before outlaying for a replacement.

Russ Drummond

 

[deejaycee_2000]

Re: Tohatsu M25C3 with no spark

When a tohatsu have no spark on a cylinder, replace the coil .... I go through alot of coils a year .....

 

[Johan Hansson]

Re: Tohatsu M25C3 with no spark

So now i have solved the problem

The cable(s) in the black tube between CDI and the coil plate was almost off.

Se the picture


I change all cables, solder on the coils ends and put on shrink tubing.



But the big job was to get the flywheel off, but that was another story...

 

[Commando C2]

Re: Tohatsu M25C3 with no spark

i had the same problem with my engine same model as yours. the loom was cut through just on the clamp as it comes out of the magneto.
Trouble is i now have a misfire so may reinvestigate the wires there as there was one wire left uncut but may have an internal break in it as the others were pretty unflexible.


what was it like getting the fly wheel off? any tips?

cheers

 

[FLBosn69]

Re: Tohatsu M25C3 with no spark

i had the same problem with my engine same model as yours. the loom was cut through just on the clamp as it comes out of the magneto.
Trouble is i now have a misfire so may reinvestigate the wires there as there was one wire left uncut but may have an internal break in it as the others were pretty unflexible.


what was it like getting the fly wheel off? any tips?

cheers

I bought a steering wheel puller from Napa, same as this one: http://www.amazon.com/Advanced-Tool-Design-ATD-3040-Steering/dp/B000OUW77A

Works like a charm. You just have to make sure to get bolts of the appropriate length and tread patten for your flywheel. I think I got M8-75mm for my 40c.

Good Luck

 

[TOHATSU GURU]

Re: Tohatsu M25C3 with no spark

You don't need a puller. Loosen the flywheel nut and bring it up flush with the top of the crank shaft. Pop it with a hammer, starting of gently and working up to "oh my God is this safe". It will come loose before you can damage anything.